It was late day, the sun setting in the distance. All of us were set up at key locations at the edges of the empire, ready to move in. We'd all been warned not to engage the guards, as it turned out 'Sombra' was a dark mage, with a horn of red crystalline stone and a talent for summoning corruptive crystal and dark possessive magic. Each crystal pony in the kingdom was completely under Sombra's control, and would not hesitate to set off every available alarm if they saw us. We all looked up and saw the moon, and then an almost unnoticeable  flash on its surface, the kind that would only be seen if one was looking specifically for it.  We all were tense, and inched ever closer to the castle. Each squad was assigned to a specific entryway to the castle, that way the castle would be completely sealed off from the possessed ponies around it that would rush to aid Sombra. My team, named Aron squad, made it in and securely barricaded off the entrance, and rushed through to the main chamber. We reached the edge of the chamber and slowed, hoping to get the drop on Sombra. We all heard the echoes of the two Princesses voices.

"Your villainy ends here Sombra, we have come to liberate those that you have enslaved and free the empire!"

We heard Luna's voice echoing around. We heard a rough voice going through the room, sending a chill down everyone's spines.

"Fools... Did you really think I wouldn't be prepared? I may not have found the true Crystal Heart, but I found something better...."

Razor Wing and Orchid snuck around to the other side of the door. We all got a good glimpse of Sombra. He was a tall stallion, about as tall as Celestia, with a deep ashen coat and a black mane. His entire form was covered in steel looking armor and a crown, drawing focus onto his face, which bore a pair of harsh red eyes illuminated with purple and green light, and his horn was just as described, a red spike with a black glow about it. He stood at odds with the two Princesses and the two captains, and he continued speaking.

"I found the designs behind them, every rune and enchantment. And with those and the help of the church, I have made something better. Oh, and don't think I haven't sensed your little soldiers. The torches about each of the castle walls monitor a wide area, so I am aware of all those you have stationed, and I have sent my brother Unitologists out to... greet them, let's say."

He showed a toothy grin, and levitated out a black crystalline heart with his final sentence, the heat emblazoned with the shape of... Oh God. A marker.

Everything hit me hard. Unitologists. The followers of the Markers, and a religion of madmen and zealots. That meant that my dream of the Marker... Crap. This was really bad. I looked up, and saw the Princesses and Captains lunge for Sombra with horns and wingblades aglow with power. We prepared to move in to join them, when a wave of energy burst from the Black Heart. Bolts of magic went wild throughout the room, and Captain Star rammed Celestia to the ground as the black lightning reached out. I watched in shock as a bolt of it went for Luna, before Captain Wind rammed her out of the way and took the blast and landed hard on the ground. This was worse than I thought, that heart had the power to instantly kill, and we were the only ones that weren't pinned down by it. I locked eyes with my team, and we all nodded. We all knew the drill, we all had been given combat plans for the case of magical artifacts.

Orchid stood back by the doorway sending magic into Shield as he charged and tackled Sombra from behind. Razor flew threw the air, sending waves of electrical wind from his wingblades into the stunned Sombra. I ran up the steps to the throne and morphed out into the shaping of a Lurker necromorph, and shot out an grabbed the Black Heart, wrenching it from Sombra's magic. I landed on the ground with the heart and rushed away, getting to Luna and Celestia's position. I heard Sombra roar in anger, and I turned around just in time to see him grab Razor's wing in his magic and use him to smash Shield away, and I saw both go down after slamming into a wall. Orchid launched a volley of magic at Sombra, and he just shrugged it off and sent a surge of power through the ground, sealing off the half of the room with the rest of my team with a wall of black crystal spikes. He turned and finally seemed to notice me. He narrowed his eyes.

"Creature I will give you this one chance to relinquish the Heart or else feel my wrath."

I could feel his magic grasping around the Heart. I knew I couldn't let him get the heart, and so I tightened my grip on the heart. Our eyes locked. I looked in the crystals formed behind him and saw Luna and Celestia charging magic, and I steeled my resolve. He spoke again.

"So be it."

His magic wrapped around the heart, and in a panicked move I transformed and wrenched my rib-cage open and pulled the heart in as I morphed my body into a larger size and sealed myself around the heart. I felt a surge of maddening rage surge from the heart and a wave of power pulsed into me. I struggled to keep myself aware, and focused on the faint hum of Luna's magic running through my mind.  Sombra sent a wave of crystal from the floor, spikes tearing into my body at all ends. I struggled for a moment in pain before morphing into one of the forms I still struggled with, but now had no fear of with the temporary boost from the heart. The necromorph Ubermorph, a regenerator capable of healing itself against most harm. I grew a good foot taller, and my arms extended out into multi-tipped blades. My vision increased as three additional eyes formed on my face. The crystals stuck through my cracked and shattered as I healed my wounds and pulled my body back together. Another row of spikes shot out from the ground in front of me, only to be caught and halted by my blades. I looked up  to see a look of confused horror on his faces. I'd almost forgotten that Unitologists worship all things necromorph, so having one o your gods show up and start wailing on you must be pretty shocking. I darted around the crystal, and made a move on Sombra. One of the tactics covered by the Guards for this kind of scenario was to actively attack the horn of the enemy until they're captured or in the most difficult of cases, until their horn was cut off to prevent magic usage. I had a feeling that this guy wasn't gonna sit there and let himself be taken in. I saw his eyes lock on Luna and Celestia.

Oh HELL no!

Rage gripped me again as I saw him sent a blast of magic towards the, and I planted myself in the way, taking the blast through my chest, tearing my torso and arms apart. I watched him rush over to me, seeking to rip the Black Heart out of me where I lay. A sickening sound of blade through flesh echoed around the room. One of my blades now ran through Sombra, starting in the end of his hoof and running until nearly hitting his shoulder. He gasped for pain, and I struggled to stand as my body painfully reasssembled and reformed. I saw his horn light up for a moment, only for him to yell in pain as I grabbed my plasma cutter in a tentacle from my back and blasted it into his chest repeatedly. I looked and saw the two sisters standing ready with magic. I slammed Sombra into the ground, knocking him unconscious, and threw the Heart on top of him. Both sisters send twin blasts of magic and the room was filled with burning white light as I ran to get some distance from the body.

I heard ponies yelling as I sank against a wall, reverting to normal. Note to self, regenerated limbs work just like the old, but when I go human again they hurt like hell.

I woke up to someone shaking my shoulders, and then smacking me while yelling at me in Razor's voice:

"JACK! DO NOT GO INTO THE LIGHT! THERE IS NOTHING THERE FOR YOU!"

I groaned and opened my eyes.

"Hey guys... wassup?"

I said groggily, somewhat out of it. I blinked and woke up further as all three of my teammates hugged me, Razor and Orchid on either side and then Shield hugging all of us. I spoke up softly.

"Um guys... I'm good for the hugging normally but my everything kinda hurts right now..."

Orchic 'eep'ed and leapt away while Razor and Shield let go. Razor spoke up again.

"Uh sorry dude. You kinda spooked us when we got back in after everything blew up and we saw you all collapsed and bloodied against a wall. We thought you got pasted!"

I gave them a somewhat pained grin.

"Well I'm still here, aren't I?"

I remembered everything that happened, and started forcing myself to stand.

"Wait a sec guys, what happened!? Are the Princesses alright? Is Sombra dead? Did we win?"

I heard Luna speak up.

"I believe I can answer that."

I looked up and saw Luna approaching us with a sad expression. I felt dread wash over me.

Luna filled us in on what happened while I was out and my team was patching me up. Sombra hadn't been kidding about having ways of keeping track of enemy soldiers. We'd only survived since we managed to get in without getting spotted, it seemed that the other guards had been heading in when the alarms went off and the Unitologists struck. Our forces had won eventually won, but at heavy casualties. Sombra had been beaten and the Black Heart destroyed, and that event ad sent out a surge of power that liberated the minds of those that Sombra enslaved, and the guards of the Empire that were inside the castle had immediately turned to our side and helped to drive off the Unitologists that Sombra had in waiting. After that our forces took out the barricades on the doors and let in all of the now-free crystal ponies. All that was left of Sombra was a charred horn, a Unitologist Marker necklace,  and the fragments of the Black Heart. But the losses...

Almost half of the Night Guard teams brought here had been either wounded or even killed. My team helped get everyone we could to the medical station set up by the crystal ponies. Something I noticed was the lack of Day Guard wounded. There was only a fraction of the number of wounded Day Guard, and no casualties. That sent a chill through me and I decided I would find out what was going on with that fact.

---

We in the Night Guard had no family save each other and Princess Luna. We all felt the loss equally, as we had all lost brothers and sisters on this day. We gave them all a short funeral, and the crystal ponies had constructed a small memorial statue, made to be of a mare and stallion in Night Guard armor. The Day Guard was in attendance, but to the anger of all the remaining Night Guard they all carried the looks of teenagers made to go somewhere they'd rather not be by their parents. I knew I wasn't the only Night Guard hearing the whispers going around among the Day Guard, and I was thankful that Luna didn't have a dragon's eye amulet like we guards had boosting our senses.

The Night Guard did find something good in the Crystal Empire though, as it was clear that thestrals and myself were completely welcome among the crystal ponies. Any whispers heard from the Crystal Ponies were positive and kind. It seemed we made a good impression upon them. We ended up staying a few days before something big happened. The elected leader of the crystal ponies, a teal stallion by the name of Geode, went to speak to Princess Luna. He spoke in a smooth voice.

"Princess Luna, we are eternally grateful for everything that has been done for us and the sacrifices made by your guard. I have been sent here by my fellow crystal ponies to ask if you would like to stay here with your Guard, and rule over the Crystal Empire? We need someone like you that can protect us from the church, and everypony here loves you and your Night Guard!"

Luna stood stock still, as did everyone around her. She seemed lost in thought, and slowly glanced at Celestia. She got a resolute expression and looked back to Geode, and silently nodded.