Celestia had found out about the swap early the next morning. It wasn't difficult to explain, but once she was certain that the changeling before her really was Max, the alicorn had been absolutely confused.

"You, and she- I do not understand. One cannot just transfer consciousness. The mind is linked to the brain and vice-versa. What you're telling me flies in the face of everything I know about how the brain works. In fact I believe if flies in the face of what you've been speaking of as well."

"I'd like to disagree, Tia, but as strange as it is, it happened. It was apparently a thing in the Hive as well. Mother would sometimes shove queens aside and use them to do things outside of the hive. In that case though the queens were just...subsumed for lack of a better word. They didn't get an option, they were just along for the ride until mother was finished with them."

Max didn't actually feel too different, riding in Seven's body. No stray urges to kill someone, the carrots didn't taste different, no need to lay eggs. Actually that last one made sense when he thought about it. Wasn't that the one thing the sub-queens were all looking for? A way to activate their ability to start laying eggs?

Max frowned, his thoughts hitching for a moment. He'd not really given it that much thought yet, but while he was waiting for Celestia, Luna and Crystal to work on ousting the castle thieves, maybe he could take a look at Seven's body. It wasn't like he'd get a closer look at a female body than this.

"I'm going to go talk to Crack," he announced, sitting up and moving towards the door. "Maybe I can figure this whole sub-queen to queen activation thing out while the rest of you are working on these bandits."

"I'm sure Seven would be more than happy to receive that as payment for her aid," Crystal giggled. "Good luck. I expect you to share any discoveries with me as well."

"Do you think I'd keep that from you?" He snorted. "After all; you're mine, little mare. I want you at top capacity. That means fixing whatever fuckery Mother worked on these bodies."

As he walked away he could hear Crystal break into giggles. Celestia was also amused by the byplay.

"Well at least it's easy to tell the difference between the two of them."

Crack was fast asleep when Max first went looking for him. Another drone offered to fetch him, drone 5334-b-79 or something like that (Max just called him Sear). Max had declined, as Crack was usually hard at work either training up the medical staff in actual surgeon techniques or sifting through the medical knowledge Max had brought to the link. The drone had already written out several scrolls based on observations and questions asked of Max. Maximus had no intention of disturbing the hard-working drone's schedule on a whim. Instead he decided to try working it out himself.

So it was that the sta-mare found HERself in front of a mirror, with her tail falling down to the right of her flank. He'd had to physically move the plates for a view of the mare-bits as the nerves were shot or turned off. Either way, he now had a straight view to Seven's...yea. That was weird. He didn't feel nearly as much arousal as he thought he should.

'Does it have to do with the damage? Maybe keep them from rutting around in the meantime?'

It would certainly make sense that arousal was next to impossible without functioning sex organs and without the proper hormones. Wasn't that a thing? There was that story of Cleopatra being seen to by a bunch of unic's so they wouldn't be 'overcome by her beauty' or something like that. While the sub-queen's had the equipment, it wasn't turned on. No working mare-bits, no desire to use them.

He frowned, using a scanning spell from the queens memories to check the nervous system of his current body. Nothing came back as damaged, but he focused on the results. Followed the magic down the nervous system right to the lower body where...still nothing was out of the ordinary.

Growling in frustration, he reached to the link and asked Crystal for her own diagnostic scan then mentally overlapped Crystal's results on herself while the scan went on. After watching the scan pass the genital region three times he was finally able to find the cut-off. A dormant nerve-cluster.

'Not damaged, just inactive.'

Actually that raised another question. If a new queen was born after Mother's defeat, would that queen develop straight to queen or was sub-queen a legitimate development phase? What about the nerve-deactivation? Was it done by Mother on a case-by-case basis or was it programmed into them?

Turning to Crack's medical knowledge it was a simple affair to awaken the nerves. After a few moments of pain as the body figured out what this strange new collection of senses and organs were, Max was finally able to start feeling a little bit of heat when either thinking of his time spent with the flock or even just staring at Seven's presented rear. The tail raised a little (as it should have), an odd warmth bloomed in his gut, and he could feel the plates shifting out of the way to allow access to the sensitive organs inside.
"Much better. Now that that's settled all I have to do is....whoa."

The sudden surge of need as the mare's canal clenched was unexpected. His eyes widened as she began to twitch and swell, the clit winking and showing itself in the mirror, the awakening of the system leading to a powerful surge in hormones as the body attempted to fix the problem the best way it could. Overcompensation.

"Oh shit. Oh shit oh shit oh shit..."

Max wobbled to the bed, his overly sensitive vaginal lips rubbing against themselves as he walked and leaving his steps shaky. She crawled into the bed and at first debated letting it pass. After all, he'd managed to wait out boners before. He had better self control then that.

Pulling his rear onto the bed his winking clit managed to brush against the sheets as she sat down, setting off a chain of fireworks running up his spine and right into his brain. Max yelped in Seven's voice before shivering. That had felt...really good.

He shifted a bit, smearing a bit of natural lubrication into the bedsheets before another wink set off another explosion of pleasure in his mind. Even the simple back and forth motion of rubbing the puffed lips on the sheets was amazing.

Max moaned deeply in the sub-queen's voice as the heat in her belly continued to grow. More, she needed a bit more. She was so close, she could feel it! Curling up as best he could he began gently rubbing a hoof over his tender sex, relishing in the simple pleasure it gave her. Each time he winked he made sure to tag her clit, driving it even higher. It wasn't far. Just a, just a bit more and-

She pushed just as the body clenched in a wink, putting a good amount of pressure on the button and once more fireworks went off up his spine. This time they didn't stop though. The spasms kept coming as waves of pleasure thundered through her mind, forcing more pressure on the sensitive nub and thus causing more pleasure. The brutal back and forth continued for a good minute before it finally started to ebb.

Panting as he stared at a wall, his body finally done with the burning arousal that activating the nerves had unleashed, he noticed a muffled giggling from the direction of the door. Grunting as he lifted his head from the bed, he saw Crystal watching from just inside the door, her hooves around her muzzle.

Max dropped his head back into the covers.

"Crystal, I swear to god. If you say a word-"

"Oh don't be like that," Crystal giggled, jumping onto the bed and wrapping herself around the smaller growling form. "I didn't really understand what was going on when I first started feeling the urges but context makes everything better. It also helps that you know about the flood of hormones and understand what's happening. I didn't have that luxury when I went through the same thing. All I knew was that the part of my body the two of you were focusing on was suddenly hyper-sensitive and all I could think about was the wondrous feelings you two were leaving me with."

Crystal nipped Max's neck, slowly moving down Seven's rented body.

"What are you do-oh. Ooo-oh no. No, no-no-no-no..."

"You didn't think you were done with just one, did you," the larger queen giggled, shifting his smaller body onto his back below her. "Luckily for you, I'm more than happy to help."

Before Max could formulate a response Crystal slipped even lower, shoving her muzzle into the already heating loins that were still wet from the first orgasm. The larger queen's tongue slipped inside the slick tunnel with no trouble, writhing about like a snake on fire.

Max stood no chance, immediately squealing from the sudden intrusion. The alien sensation, the complete ridiculousness of the situation as well as his still rising heat left his mind devoid of thought, capable only of staring at the ceiling as Crystal ruthlessly worked him over. Her tongue was everywhere at once, causing Max's body to spasm with the overwhelming pleasure running up her spine. Then the tongue was gone, replaced moments later by another explosion of pleasure as the larger queen seized her pleasure-button mid-wink.

'Oh shit oh fuck oh shit, shit fuck shit...'

Crystal giggled into his sex and shifted a bit, slipping her tongue inside again in such a way that it brushed against Seven's clit the whole way in. His back arched and she let out a gurgled scream, unable to do much more in his current state.

'Already losing mental cohesion? Didn't you make fun of me for the same thing?'

'When I, when I get my dick back-Oh fuck! Oh, I'm going to rut you until you can't walk straight.'

'Sounds fun,' Crystal answered slyly.

Max panted, his brain finally learning to process the intense pleasure.

"I'd tell you...to fuck off... but this is almost painful. Keep going."

Crystal giggled into his sex again, making him shiver. It felt amazing and the need was just so strong right now. At least when Crystal's sex had been reactivated they'd been mid-fuck.

'Yes, I was very fortunate,' Crystal responded, leaving Max to wonder just how tight of a grip the mare had on his existence at the moment. 'I don't know if I'd have been capable of dealing with those sensations. With all of the new things that were going on and with so many new ideas being thrown at me, I was confused. Scared, as well even if I didn't understand why. But my new hive, my new family was right there to make me feel wanted, needed, and loved.'

'You and Luna, you two gave me a purpose. A focus, a goal to work towards. Now I'm strong enough to push around one of the bigger sub-queens of the Hive. I'm curious how Seven will respond once she trades back with you. What will she do after being exposed to all of these repairs?'

Max felt her body clench as Crystal buzzed her wings, setting off a new wave of tingles through the body. The large queen giggled before extracting her tongue, causing Max to let out a moan of disappointment.

'Oh don't worry, Max. We're not done yet. I'm just getting bored.'

Standing over the smaller mare and stepping around Max, Crystal rested her body on his, leaving Crystal's now-exposed nethers facing Max.

'I'm willing to help you, but relationships are give and take, right? How about giving some attention to me as well?'

Max tried to laugh at the turn around, but only managed a weak gurgle as the larger queen used a bit of telekinesis to bury his muzzle into her sopping marehood.

'Fine, I guess I can, spare the time.'

Crystal hummed in delight as Max finally got started, finding the larger queen already worked up.

'You and Luna both, I swear,' Max thought with a grin, happily beginning to pleasure the flock's beta. 'Mention sex and you two come running. Then you just cum.'

'Oh it's not like you're much better. You started this after all,' Crystal shot back, pressing her body back into his muzzle. 'You're the one who started this mating for energy thing with Luna. It feeds me and it feels amazing. Why would I not love it?'

Max mumbled his agreement, causing Crystal moan as the vibrations traveled into her body. His own body, or at least the one he was borrowing from Seven, was starting to burn again from the hormone dump he'd unleashed.

'Crystal, Crystal do something, it's starting to, to hurt.'

The queen did do something, just not what he was expecting. She began stroking the needy lips of the smaller mare's marehood tauntingly before opening the link fully, sharing her own pleasure with Max. Then, even as he was wrestling down the sudden surge of pleasure, the uppity beta began returning the pleasure by once more driving her tongue inside Seven's depths.

Having barely been able to maintain coherence while being eaten out, the doubling of the sensation was enough to finally fry Max's brain. The male riding in Seven's form began to spasm in the first throes of orgasm. He wouldn't remember anything else for the rest of the morning and well into the afternoon.

Several hours later Maximus was sitting in front of a mirror, the lower portion of Seven's body transparent except for the extensive reproduction system. It was almost silly in its complexity, so many bits and bobs in the body that came off of the vaginal canal. It was difficult to keep track of it all. For that he'd started color-coding the different bits. Blue were storage, or sperm sacs. Red was actual egg production, while yellow were egg storage sacks. The ovaries and stores were usually close to each other and in some cases the muscles for the tubes connecting them, as Max and Crack had learned from observation and stimulating the muscles directly, were fully capable of moving eggs from the ovary to storage then back out and into the mixing-pouches.

Said pouches had both a direct connection to he vaginal canal for laying as well as to the seed-pouches, serving as a mixing vat for the eggs and sperm if fertilization needed to happen a long time post coitus.
'It's like the perfect breeding machine,' he marveled, flinching as Crack used a bit of magic to stimulate another set of muscles as they mapped out the organs.

"I never thought I'd get the chance to do this, actually," Crack mumbled. "Most queens won't let you near their reproductive organs even if they've been badly injured. How did you end up swapping with Sub-queen Seven?"

"She actually volunteered," Max explained. "I was looking at the possibility of a long-term infiltration and she swapped because she was convinced I'd muck it up. I figured I'd do this while everyone else is working on the problem of Copper Road Keep. Be slightly less useless."

Looking over the organs, Max frowned. He'd already checked the ovaries and with the return of hormones to the body they were starting to produce eggs. The issue was he didn't know the mechanism for getting the body to ovulate.
"It's might be in the brain or something. Maybe something like a, a subconscious act. Like breathing or a heartbeat. Wasn't there a part of the brain that was specifically dedicated to involuntary actions?"
Suddenly his eyes lit up. He turned his head, a flash of fire leaving the brain and spinal column, or at least the changeling equivalent, visible in the mirror.

"Crack, we have a new project. I want to know every part of the lower brain and what it does.

At the uncomprehending stare, he rolled his eyes.

"If reproduction is so ingrained in changelings, it may be instinctual. Egg laying may be one of those things a queen doesn't hunk about but with such an extensive reproductive tract there has to be some processing power dedicated to it. There has to be some way for the body to process which sacks are full, which are empty, which ones need to be emptied into the other parts. Hell, with so much dedicated to egg laying I wouldn't be surprised if it was a larger part than the bit that regulates heart and lung function."

It took working through the next day to figure out which bits of the brain weren't dedicated to egg production. The solution left both of the male changelings irritable, too. After all, drones wouldn't have the extra sections of the brain a queen would have if the issue was related to the nervous system.

With a sleepy Flick standing next to Max(who was still renting Seven's body) the two made a few startling discoveries.

For one, both the queens and drones spinal cords actually acted as receivers to the hive link. Queens had an extra bit though, an entire additional length that ran down their back that acted as a powerful transmitter while drones only had a small section to transmit. Most of their nervous system was dedicated to either receiving orders or transmitting information. There was also a section that allowed a drone to receive direct input from a queen, allowing a queen to 'ride' a drone for a time.

Queens were a whole different story. The brain had several additional segments including a small area near the brain that apparently contained the hive. For Seven the section was undeveloped while Crystal's was extremely active, growing to accommodate her hive. Max could only guess what his own brain would look like. Breeders could link, but his first link had been to a queen. Sure a lot of the parts in their shared link had been influenced by him but Max was easily more mentally developed than Crystal was at the time. They already knew that Crystal was adapting a lot of Max's mannerisms and attitudes; it would surprise nobody to learn that his influence continued into the development of the hive. Having been using that bit of her mind for longer, Crystal was capable of controlling more drones than Seven was at the moment.

While the information was interesting, there were several bits of the changeling brain that a queen had while a drone didn't. It would be a while before Max was finished looking, and even then there wasn't a guarantee that he'd find what was locking them out. It was something though. Another step closer to giving the changeling species a future to look forward to.

It was nearly four days later, Crystal having already arrived with Luna to oversee the siege of the Keep as well as the removal of the bandits, that a breakthrough was made. It wasn't even during any specific tests or studies. Like many wondrous human discoveries, the answer was found while the scientist was screwing around, bored.

Max was resting on a couch near where Celestia was writing out some new legal precedent, one that would give any species in the Keep the same protections ponies were being offered. She'd not really considered it before but with the diamond dogs as well as the changelings, as well as Maximus' word that they'd be dealing with other species eventually, she'd decided to get it out of the way. The fact that such a thing had to be written had bothered her a little. She also made certain to specifically mention all pony tribes, including alicorns. After that, she began working on catch-all's to make certain a species wasn't excluded for any reason.

"What was the word, Max? Not intelligent, but-"

"Sapient. Able to reason."

Max was on her back, looking up a clear hoof. Changelings were nothing if not masters of their own bodies and he'd taken to lighting nerves with a minuscule amount of energy, allowing him to watch the energy flow down the leg and into the spine.

Of course, it wasn't running actual energy down the nerve, just a bit of emotion around it. He'd made that mistake already and ended up needing Crack to undo an extremely painful nerve-burn. The drone had been less than pleased at the extra work.

Watching the glow run up the leg and into the body, Max shifted the rest of his body into the mostly clear form, leaving the spiderweb of nerves the only thing darkening the otherwise clear form.

A shiver of revulsion passed through Celestia as she looked up at the use of changeling magic but it passed quickly. He'd been doing this for several days now and it has lost a good deal of its shock value.

Up to the spine. Pick another line and follow a path. Try not to use the same one as last time. Follow it down the spine till about...now. Follow the line through the body till you reach the endpoint. Hot and cold nerve there, a pressure nerve on the other side. Follow it back up and run to the spine. Follow the chain back then run back to the body.

Up, down.

Up down.

Up, Dow-

Max perked. The nerve chain cut off suddenly, much like a few others the queens were incapable of accessing. One had been a little thing that inhibited a queen's ability to trust anyone, even other queens. After conferring with Crystal and reconnecting the nerves the flock had theorized Crystal would be less likely to fall into her mindless obedience again since her ability to trust her flock was no longer solely from her connection or her beta attitude. Another cluster had resulted in dampened empathy. Still another had been a warped cluster in the brain that doubled the amount of happiness a queen registered in seeing others in distress.

As with any experiment regarding the nerve clusters and the brain, Max pinged Crack that he'd found a new bit of the queen's body that wasn't connected properly. The second he received a ping back, Max used a bit of love energy to stimulate the body to turn on the nerves.

He waited, running through the mental checks they'd developed, trying to figure out what the damaged nerve had been influencing.

'Not anger. Not love, doesn't feel emotional at all. Where's it based? That's part of the medulla, right next to the glands. Right next to it-'

Max's thoughts were cut off by an odd sensation rolling through his body. He frowned, the odd tickle making him lose focus on his transformation and flashing back to the chitin covered form of Seven. He mentally began running full-body scans and was just about finished when his rear legs twitched.

"Oh fuck...oh shit, oh fuck-fuckity-"

'Crack! Office, now! Bring help!'

'Sedatives or bandages needed?' The drone replied, already moving.

'No, I found it! Towels, lots of fucking towels. And honey! Oh shit, shit'-"shit, shit, shit!"

"Max? Maximus, what happened?"

He rolled off of the couch even as the Seven's body began going into overdrive, burning extra energy to accelerate the growth of the eggs. The body ovulated for the first time and pulled the eggs along into the connected chambers, attempting to mix them with seed. There was none present(Max wasn't that curious), so after a few odd pulses where the body was squeezing an empty sperm-sack, the egg moved on. The eggs were pushed into the vaginal canal that was already being flooded by a thick, lubricating fluid that would aid in the laying. The same lubricating fluids that were beginning to leak from the still-covered vagina. Max found himself instinctively shifting into a laying position even as the door was knocked off its hinges, three changelings barreling over the knight that had been getting ready to knock.

'Towels all around. We don't have a laying chamber so- Sear! The windows!' Crack shouted, throwing orders left and right. 'Eyes are dilating, light sensitivity is going to skyrocket.'

Max winced as s/he felt the first egg being pushed down. Two drones began setting towels down and prepared to catch the eggs as they came.

He couldn't see or hear anything, his eyes burning even as a drone closed the windows. A moment later, something was draped over his eyes.

"I'm right here, shh. You're fine, safe. I have you."

Max grunted again, feeling an egg pass from his body. She moved forward a little, latching her forelegs around Celestia's neck as his body continued to work out fresh eggs.

'Honey.'

It wasn't a minute later that a large jar was pressed to her muzzle, letting Max guzzle the stored emotions while Celestia relaxed from the lessened strain on her own emotions. Another jar followed as he finally started evening out from his bodies sudden burst of activity. Another egg began its journey out of her body, then another, and another...

The changeling panted as he held weakly to the alicorn, noting the small pricks on her neck and the blood that had dried.

"Sorry...'bout the blood..."

"It is of no concern," Celestia responded, yawning. "The drain on our emotions from your unexpected energy burn was a bit more disconcerting. I feel a little...flat. Tired, as well. I must ask though. Maximus, would the foals refer to you as their father...or their mother?"

Max sat there for a moment, staring at the princess's neck.

"I don't know what kind of venom Seven has. Would you like to find out?"

Seven walked through the forest with her head, or rather the head of the Breeder, held high. With her superior experience, she'd been able to direct the pony forces in taking the Keep with only a few losses. The serving staff had been evacuated, along with the Breeder's form, in a tunnel dug by a strange bipedal creature whose digging capabilities put the best-fed burrowers to shame. The diamond dog, as Crystal called them, swam through the earth. There was no discernable effort involved. One was even able to rip apart the stone walls of the individual cells, leaving nothing to stop the ponies from running down the entry tunnel and making it to safety. Once Seven and the prisoners were free, a small group of knights along with Crystal filed into the tunnel, readying an ambush for the bandits.

Seven found herself deep in thought, though. She'd taken the bandit mare who she'd been impersonating with her. She wasn't sure why, but she felt like it was a good idea. No other option would be available to her so the mare would be the queen's own personal servitor. That or she'd be executed for banditry.

'An offer she can't refuse, I believe it would be called,' the queen thought wryly.

The Keep was in full alert by now for all the good it would do. The sounds of explosions from spells were reaching her even from her current position. She watched with disinterest as the prisoners were seen to. Some were being given food or water, some were being treated for a few medical issues. One seemed to have a bad infection on an ear. Too much longer and it may spread to the pony's skull and brain.

Seven scowled as she found herself staring at a mare's flank. The male's body was apparently flooded with something called testosterone, which made him crave a mate. The longer he went without releasing his seed into a female, the stronger that desire for a mate became. She already knew the male was almost constantly copulating with Crystal and the large blue mare, Luna, so the sudden cut-off left him antsy. Or rather, it left her antsy. The opposite, something called estrogen, was supposedly something the male had recently unlocked in her own body a few days ago. While she didn't like the idea of the male doing things with her body while she was in his, Crystal had shown Seven the images from a drones eyes at the castle. Eggs could be seen developing in Seven's body now if he shifted into a glass-like form. If a couple strange chemicals were necessary for the production of eggs, than Seven would...she would just have to accept that maybe the breeder knew what he was talking about.

Looking back to the castle, Seven listened as the sounds of battle finally started to run their course. She wanted to get back to her own body of course, but first she had to make certain the others knew why she was carrying the pony, as well as waiting for the pony to finally wake up. The venom she'd used would be fading right around the time the ponies were ready to stop for midday meal. After that, the breeder could carry her new servant back.

Several hours later, her cargo shifting on his back uselessly and radiating terror, Seven finally found Luna and Crystal together, both speaking to two smaller ponies. One was an important prisoner, the previous ruler of the castle that was now likely a shattered pile of stone. The second was some silver Pegasus. Upon seeing Seven, Crystal had nearly squealed in delight, rushing over and pulling the male form she was riding into a crushing hug.

'Dream-link! Now! You need to see this!'

So thrown off by the stronger queen's giddiness Seven almost didn't remember to retrieve her captive, who was thrown clear by the hug. A quick glance to Luna revealed nothing more than an encouraging smile, though there was a lingering taste of excitement present. It wasn't battle-lust either. It was...anticipation.

Seven went along with the crazy creatures as she'd been forced to before, not really bothering to hide her irritation. Laying next to Crystal after making certain her prisoner couldn't escape, Seven delved into the dream-hive, finding Crystal and several drones yammering loudly while looking at a projected image that was showing a drone's current focus. In the focus...
'No...'

Crystal saw her staring and grinned happily, pulling Seven into another hug.

"Congratulations, Queen Seven."

Author's Notes:

I'll likely get a few "That doesn't work that way!" or "But that doesn't make any sense!"

I want to say I don't care, but that's not true. I think it makes sense. A species of shape-shifters would find control of their own bodies much more innate than any others. In this case, the complete control makes sense to me.

If your issue with the science-y or biology bits I used, please, feel free to explain where I was wrong or what you think it should be.