"All of the obstacles to Celestia's rule — from Discord to Sombra — have been are eliminated, and now the Lunar Princess herself is gone. Supposedly, she went mad with power in the middle of the night, and Celestia was forced to banish her to the moon. Convenient, no?"
–Mercurial Blade, House Argent, 1CE

Officially, Thunderball was still an officer in the Special Air Service Regiment of the Royal Army. Most officers spent their time either at the regimental headquarters supervising the training of recruits or managing intelligence and logistics. A relative few would be deployed on missions, either for the Army or at the behest of numerous government agencies who had need of their skills.

There was a train leaving later that afternoon which would have taken him back to regimental headquarters. He had plenty of time to head down to the station after being wheeled out of the hospital and buy a ticket. Instead, he found himself walking in the opposite direction, towards the new castle.

It was majestic. It was an eyesore. It was lifeless.

Princess Twilight had yet to hire any staff. It was a rather jarring anomaly amongst royalty; even Blueblood had a fully staffed manor, which thankfully kept him far away from Equestrian society.

Thunderball paused before the castle door to take in a deep breath before he knocked. The door swung open as he reached out with his hoof to reveal a small purple dragon.

"Afternoon," Spike greeted brightly. "Saw you coming down the street from the kitchen. Everything alright? You seemed kinda out of it."

"Just had a lot on my mind," he replied evenly. "May I see the Princess?"

"Of course. She's in the library." Spike pointed upwards. "It's the room with the telescope pointing out a window. Can't miss it."

"Thanks."

Thunderball flapped his wings and took off into the air. A wide grin spread across his face as the wind streamed through his mane; this was his first flight outside of physical therapy sessions in months, and it felt so incredibly liberating. He stretched his wings wide and let a gentle breeze carry him into the library window.

This library was much larger than the Golden Oak Library. It consisted of one massive room lined with shelves from floor to ceiling, with long oak tables laid in the center. Twilight was currently halfway through reshelving a small cart full of books in near the window. Thunderball chose to glide down next to her and land in a kneeling position.

"Your Highness."

Thunderball's long and eventful service had prepared him for many things, but a princess squealing in joy and hugging him was not one of them.

"It's good to see you too," he said delicately.

Princess Twilight shot him a radiant smile. "Sorry if I got a bit carried away there. I must say, it's a relief to see you out of the hospital — looking as fit as ever, may I add."

Thunderball stuck his chest out proudly. "The doctor said I should be fully recovered, so I decided to take you up on your offer at the first opportunity."

"That's wonderful!" Twilight clasped her hooves together in joy. "I could use a head butler to help look after this place."

"Wait, a butler?" Thunderball's hair shot straight up as Twilight gave him a stern glance. "Not that I wouldn't be honored to serve you, Your Highness," he added hastily.

The tension in the room broke as a smile tugged at Twilight's lips. "Well, if being a domestic servant doesn't appeal to you, then I suppose you should follow me." She led him to one of the tables, which had a map of Ponyville and the Everfree Forest on it. "I have another project in the works, the restoration of the Everfree Castle, reclamation of valuable information and artifacts within it."

Thunderball nodded eagerly. "Now that sounds more interesting. I can definitely help with that. May I ask what you're restoring the castle for?"

"Now there's an interesting question." Twilight sat down at the table and rested her head on her hooves thoughtfully. "Thunderball, how would you feel about Celestia allowing changelings to openly live amongst us?"

Images of fangs and chitinous armor flashed through Thunderball's mind. They had killed his friends in a botched raid on a changeling hive, and nearly crippled Equestria when they attacked Canterlot. But that had been at the behest of Queen Chrysalis; changelings like Creme Brulee wanted nothing to do with her plans of conquest. It would hardly be fair to treat him as the enemy, or force him to life a double life.

"I would not oppose it," he answered slowly, "Though I doubt most ponies would feel as I do."

"Yes, and that's the problem. How can we allow defectors to live peacefully as full members of Equestrian society when they face so much distrust? How can we have peace with Chrysalis if nopony really sees changelings as anything but monsters?"

Her horn glowed purple and words appeared on the map, right above the ruins of the Everfree Castle. They spelled out "The Everfree Colony".

"I think I understand. You wish to give changelings a safe haven and a chance to prove that they are not a threat to Equestria."

"Exactly," Twilight beamed. "And I can't think of a better place to build a friendship between ponies and changelings than Ponyville. Three races of ponies already live in harmony here, and I am confident that we can include changelings."

"An ambitious plan." Thunderball read the words on the map again and frowned. "A risky plan. I don't think we're equipped to deal with a large influx of changelings. Who do you intent to have watch over them?"

"It is a difficult question, to be sure. Qualified ponies are few and far between; we no longer have any families with a tradition of espionage or diplomacy, and our government employs too few intelligence agents." She shook her head sadly. "Sometimes, I think it's too bad we can't drag House Argent out from the grave."

Thunderball snorted. "Surely we could do better."

Twilight raised her eyebrows. "Looks like somepony's been reading up on the Lunar Rebellion."

"I know plenty about House Argent," he spat. "One of the first unicorn houses to betray Celestia. Responsible for crippling the loyalist forces during the start of the war through disinformation, espionage, and assassination. I doubt they'd be of much use in this day and age."

The sheer intensity of Thunderball's voice (for a family long since lost to history, no less) caught Twilight off guard. "In their defense, they rebelled because they suspected Celestia was trying to pull a Sombra; they did switch sides again halfway through the war when they realized the rebel leadership had been corrupted by dark forces seeking to free Nightmare Moon."

"Too little, too late," Thunderball snorted. "It's pretty hard to make up for helping start a civil war."

"It is, but they did pay out heavy reparations after the war, and adopted many war orphans. It might not make up for their mistake, but the important thing is that they were sincere."

"With all due respect, Your Highness, that is a ridiculously lenient opinion."

Twilight narrowed her eyes and spread her wings. "That happens to be Celestia's opinion. She taught me about the Lunar Rebellion herself, and said she was saddened by how there was so little forgiveness after the war. Many of the old houses withered from lack of heirs to the bloodline, and Equestria suffered from their loss."

Thunderball kneeled again. "I suppose Celestia knows best. She was there, after all."

An awkward silence filled the room as Twilight stood up. "Look, please don't do that. I–I'm not angry as you, I just got a bit touchy when you dismissed Celestia's opinion. Can I ask you to stop saluting, bowing, or kneeling in front of me? At least not so frequently?"

"You may ask, Your Highness." Thunderball raised himself off of the floor, but kept his head lowered slightly out of deference.

"How many times have I told you not to call me that?"

"Thirty–seven," Thunderball replied without hesitation. "Your Highness."

"Is it ever going to work, or do I have to make it an order?"

Thunderball's cheeks blushed a light–pink. "My apologies. It's something of a habit."

"Well, I can certainly understand that," Twilight chuckled. "I can get the same way myself. And don't even get me started on my friends. You have no idea how hard it was to convince Pinkie Pie not to throw you a 'Leaving the Hospital' party in the reception area."

The thought of how Nurse Redheart would have reacted to one of Pinkie's parties brought a smile to Thunderball's lips. "I'm surprised you managed to talk her out of a party at all."

"Oh, I didn't," Twilight commented lightly, as her horn lit up.

Banners unfurled from the ceiling as confetti filled the air. Pinkie Pie appeared from out of nowhere and placed a party hat firmly onto his head as a dozen voices shouted out at once.

"Surprise!"

The painful sensation of needles intruding into Thunderball's skull woke him up the next morning. He wrapped his pillow around his head in a desperate, but ultimately futile, attempt to block out the pain. Several minutes were spent cursing the existence of Pinkie Pie's Super Special Sugar Punch before he realized that his bladder was full, and that if he did not take care of it soon, he would soon be having a very embarrassing conversation with Twilight.

Thunderball tried to lift up his blanket, only to find that it was being weighed down. He reached a hoof out to figure out what it was and encountered something soft and warm.

"Morning, sunshine."

Rainbow Dash's voice drifted into Thunderball's ears and nearly caused him to roll out of bed. His eyes shot open to reveal that he was in one of the sparsely furnished guest rooms of Twilight's castle. Rainbow Dash was lying on her side next to him, reading his copy of Daring Do and the Songbird's Lament.

"What are you doing here?" Thunderball's voice cracked slightly due to stress and dehydration. "I didn't do anything regrettable last night, did I?"

"Nah, you're ok." Rainbow put away her book and stretched out next to him. "In fact, I think doing me was the best decision you've ever made."

Thunderball's jaw dropped as he struggled to process the statement, while Rainbow shot up into the air and put her hooves on her hips. "We could become a real power couple, with my brawn and your beauty."

"Please tell me you're joking." Thunderball gently massaged his temples as he waited for a response.

"Aw, don't get your feathers ruffled. Nothing happened last night." Rainbow glided down to his side and gave hit him with her tail. "Though I suppose I should be insulted that you find the idea of sleeping with me so awful."

Thunderball rolled his eyes as he swung himself out of bed. "Aren't you a little young for me?"

"Psh, what's a decade here or there? I'll have you know that plenty of ponies of all ages would kill for a piece of this flank." Rainbow emphasized her point by giving herself a hearty smack on her cutie mark.

"Count me out, then; I kill for business, not pleasure."

Thunderball nudged past Rainbow Dash and trotted out the door. He immediately froze as he saw Twilight standing in front of them with several clear crystal rings in tow.

"Wait, I can explain!" Thunderball waved his forelegs frantically. "It's not what it looks like!"

Rainbow Dash stifled a giggle from behind him. "What does it look like?"

Twilight raised an eyebrow at their antics. "It seems like Rainbow Dash woke you up."

Thunderball cleared his throat awkwardly. "In that case, Your Highness, it's exactly what it looks like."

"Right…" Twilight turned away from them and returned to crystals. "I'm going to go to the library. You can join me if you want, but don't disturb my research."

"Nah, thanks for the offer Twi, but I gotta teach a karate class for kids."

Thunderball quickly checked his ears for a wax buildup. There had to have been some miscommunication. "You teach karate?"

"I don't like your tone, buster." Rainbow tapped him on the nose playfully. "What's so hard to believe about me doing karate?"

"I didn't mean that, I'm just surprised that you teach kids."

Rainbow proudly stuck her chest out and tossed her mane back. "I just think I have a responsibility to help my fans be as awesome as I am!"

"...of course you do."

"In fact, now that you're here, I think I should invite you along! What do you say to some martial arts madness?"

Thunderball looked between Rainbow Dash and Twilight's retreating form before nodding. "Sure, just give me a moment to talk to Princess Twilight and I'll meet you there."

Rainbow Dash nodded and quickly flew out through the nearest window, while Thunderball made a beeline for the library. He found Twilight seated at the main table, still toying with her crystals. He counted a dozen rings, all made of the same material.

He gently cleared his throat as he drew near. "Pardon me, Your Highness, but are those from the Crystal Empire?"

"A gift from Cadance, as a matter of fact," Twilight nodded. "Something to help me in my arcane research."

"Those wouldn't happen to be mana prisms, would they?"

"Thunderball!" Twilight looked at him with wide–eyed amazement. "I'm impressed. Not even many unicorns know about mana prisms these days!"

"Oh well…" Thunderball's eyes quickly shot to the shelves full of books surrounding him. "I think I read somewhere about how unicorns used crystals as a means of focusing their magic with greater efficiently as an alternative to channeling more raw power through their horns."

"And rightly so," Twilight nodded. "Using external sources of power such as the Alicorn Amulet, a Stone of Jordan, or Shard of Midnight exposes the horn — and by extension, the brain — to more energy than it can safely handle. Mental instability commonly develops from prolonged use, and can become permanent in severe cases."

"Like that Zanzebran sorcerer a few years back? The one who tried to summon dark creatures with an ancient zebra fetish?

"Conrad Konik? I believe so. Used the Heart of Darkness and his own daughter to try and open a dimensional rift. I heard whatever came out of it wasn't too friendly and tore them both to shreds. Terribly tragic."

Twilight laid her collection out in a semi–circle on the table. "It's a pity all artificial aids acquired the same stigma; I think most unicorns would benefit from a good set of mana prisms, say, twelve or so — though I think you can get by with eight, if you're only concerned with covering the basics."

One of the rings floated up between the two ponies, so that Twilight could look at Thunderball through the center. "I must say, you keep finding new ways to surprise me! Got any other secrets I should know about?"

"Nothing from you, Your Highness." A bead of sweat trickled down the back of Thunderball's mane. "If you would be so kind as to excuse me, Rainbow Dash invited me to her karate class, and I would be interested in attending."

Twilight's gave him a friendly punch on the shoulder. "Of course you're excused. I can't have my trusty bodyguard get rusty, now can I?"

Thunderball quickly bowed his way out and slowly walked outside. A talent for deception was a requirement for covert operations, but lying to Twilight bothered him in a way that he had never felt before. Twilight was more than just a superior to him; she was his friend and he had betrayed her trust.

But there was no harm in keeping a few things from Twilight, was there? It was unlikely that his cousins would try anything drastic, and there was no point dredging up old business just so he could feel better about himself. Sometimes, it was better to let sleeping dragons lie.

Instead, he thought about the existence of a dojo in Ponyville. The presence of a Japonese martial art was not terribly unusual, though, in his opinion, it catered more to the competitive sport crowd. Karate demanded certain restrictions on the practitioner — tied wings for pegasi, arcane–locked horns for unicorns — that created an equal playing field for all ponies, but did not reflect how fights played out in the real world, excepting instances where the combatants were disabled.

The dojo looked like a dance studio from the outside, but the interior was decorated in a traditional Neighponese aesthetic. Paper screens were stacked around the walls, and a large square made out of bamboo mats in the center denoted the training area.

It was currently occupied by Rainbow Dash, who was lead a class through stances in the middle. To Thunderball's surprise, there were several adults practicing alongside the children, including Creme Brulee. While Creme was definitely strong, karate was more concerned about finesse and form. Most ponies of Creme Brulee's build tended towards boxing or wrestling.

Thunderball waited by the sidelines until the class took a break before waving at Creme Brulee. "Didn't expect to see you here; did Rainbow rope you into coming as well?"

"Me?" Creme Brulee twisted his white belt nervously. "No, I just saw a flier for self–defense lessons and thought it'd be, you know, a good way to pick up self–defense skills."

"On one hoof, it is. You can build up strength and self–confidence through martial arts. On the other hoof, you have to think about if the curriculum is relevant to real–life situations. A quick jab is very useful; a spinning back–kick, less so. I personally find the mental discipline more useful; a well trained mind is capable of amazing feats. Emotion suppression, pain tolerance, the ability to enter a death–like state, resistance to mind control, etc."

Creme cocked his head. "Is that what you were talking about at the hosp–"

"Heeyah!" A multicolored blur flung itself between between the two ponies with a flying kick. "About time you showed up!"

"Nice to see you too, Rainbow." Thunderball paused and looked at the belt around her wings. It restricted their movement, but he supposed that was the point. Karate was a competitive sport which placed numerous restrictions on the practitioners to create a level playing field. Pegasi wore their belt over their wings to prevent flight, and unicorns were doubtlessly unable to use arcane magic. "I see you're a black belt."

"Yup! And fully credentialed to teach as well." Rainbow proudly turned around on the spot. "Care to see what it's all about?"

Thunderball could not help but grin as he stretched his wings. "Are you asking me to step into the ring?"

All he received was a cocky grin from Rainbow as she turned sideways and balanced herself on her hind legs. The dojo became as quiet as moonbeam as Thunderball pried off his horse shoes and stood in front of Rainbow Dash with all four hooves on the ground, as if he were casually waiting in line for a cupcake.

They stared at each other for a moment before Thunderball suddenly flapped his wings and pushed off of the ground, lashing out at her with his forehooves so suddenly that they caught Rainbow in the chest. She stumbled back and shot to the side. Thunderball saw her chest fill with air as she breathed in — an improper breathing pattern that restricted air intake, only done when breathing properly from the diaphragm would interfere with the muscles used for kicking.

His hooves instinctively shot down as she deployed a textbook front kick with her left leg. He caught the limb and pulled it towards him, causing Rainbow to stumble forward while he shot around to her left. She quickly recovered and turned to face him again. Thunderball saw her diaphragm expand this time – breathing properly indicated an upper body attack, so he raised his forelegs as she pelted him with a blazing assortment of punches. Thunderball kept his forelegs close to his body in a tight defensive posture and blocked each attack, even as the sheer quantity of strikes forced him back against the edge.

Just before he would step over, Thunderball deflected a punch with his right foreleg and twisted with the blow while grabbing the front of Rainbow's gi with his left hoof. The move unbalanced her enough for Thunderball to slam her into the mats face first. The audience gasped as she rolled onto her back and flailed around on the ground.

"How the hay did you… I'm faster than you!" She grumbled, as her hooves found purchase on the mats.

Thunderball placed a hoof on the back of her gi and pulled her upright. "Faster, yes, but also predictable. You also give yourself away by your breathing. Exhale before attacking, and be a bit more flexible."

"Flexible. Yeah, got it." Rainbow snorted impatiently and assumed a fighting stance. "Up for round two?"

While Thunderball had his reservations, it would probably be best to let Rainbow's competitive streak wear itself out. He assumed his fighting stance again as she came towards him with a tremendous shout. Her breath left her body before she committed to a flying kick. It fell far short of the power and speed of a true pegasus flying kick, which would normally be augmented by their wingpower.

Thunderball was able to react before she reached him and lowered his body. He bucked at Rainbow as she flew over him with both rear legs, catching her in the back. She went flying towards the edge of the sparring area, but landed on her forehooves and quickly assumed a low sidewise stance. She launched herself into another flurry of strikes at Thunderball, faster than last time, but not quick enough to overcome his defenses.

Thunderball sensed an opening as Rainbow Dash threw a punch at him with her left hoof and sidestepped it so he could deliver a blow to her chest. Her right hoof, which had been blocked from his view by her body, shot out and latched onto his foreleg. Rainbow then leaned back as her right leg delivered a front kick to Thunderball's diaphragm.

The kick caused him to collapse onto the ground, but not before dragging Rainbow down with him. The two continued struggling and rolled right through one of the paper screens. When they came to a stop, Thunderball was straddling Rainbow Dash, pinning her forelegs above her head with his right hoof while bearing down on her throat with his left foreleg. They breathed heavily as they glared into each other's eyes, until Thunderball abruptly released her and ruffled her mane.

"Good kick," he chuckled as he rolled off of her. "I'm going to have to decline any further matches with you for the day, though; you took the wind right out of my sails."

Rainbow Dash looked more pleased than she had after her first defeat, and propped herself up on her elbows. "Then I claim ultimate victory due to your forfeit! Muhuhaha!"

Thunderball rolled his eyes, but did not contest her declaration.