Today had started out so simple for Twilight Sparkle, she had gathered her friends she had made a few days before to tell them the news.
"Princess Celestia sent me a letter, and she wants me to bring you all to the castle for a tour!" She said with joy.

Her friends all reacted to the news with excitement and an hour later they were walking through the castle gates. Celestia had greeted them personally and they were all having a good time. Then Celestia tensed up and said that she felt something wrong. Soon after there were howls and shouts about monsters filling the air. Celestia led the group of mares to a safe place and ordered the guards to go protect the citizens of Canterlot. They had huddled together in fear and waited for it to be over.
When the guards came back carrying four unconscious foals they had been horrified by their disfigurements and feared the worst. They rushed to the medical ward and laid the foals onto hospital beds before going to report everything to the princess. Then an hour later a nurse tried to cast a healing spell on the colt with the black mane. The colt started projecting a wave of terrible darkness, Celestia rushed in and she and Luna went into the his mind. Twilight could only watch as the princesses were left at the mercy of the monster they found in the colt's mindscape until the colt woke up.
Then the colt and his friends woke up and tried to leave, and when the guards tried to stop them they pulled out weapons and attacked the guards. Just when the guards had almost captured them the grey colt released a surge of dark magic and tore through the remaining guards.
When they introduced themselves the grey colt, Corvalius Dakenistaire she reminded herself, had refused to answer any of her questions, rejected Pinkie's offer to be friends, threatened Rarity, and got violent when he saw Applejack. Now he was walking away to do who knows what.
She tried to use her magic to stop them but nothing happened. It felt as if her magic was refusing to touch the group of foals. Desperate to keep them from wandering off and getting hurt she ran after the foals. She tried to grab them but it was like something pushed her away every time, so she settled for following them as they wandered through the castle to keep them out of danger and help them when they got lost.

Corvus walked through the hallways of the building they had awoken in, barely suppressing their daiyoshi to avoid harming their friends. The purple one, Midnight Sprinkle or something, was still following them. She tried to capture them with her strange energy but it was easily repelled, they would have to study this energy to determine its capabilities. Then she tried to grab them only to be forced back by a mental push form Corvus. Deciding to break the silence Corvus spoke.

"Why are you following us."
The purple equine looked startled by their question and responded "To keep you safe of course"

"We don't need your protection.

"Of course you do! You're only little foals!"

'There's that term again. Why do they insist on calling us that?' Corvus pondered while walking.

"Then make yourself useful and tell us where to find a wide open area with no distractions."

"Well, there's the guards' training grounds."

"Take us there, now."

"Why should I?"
Instead of answering Corvus twisted their head to look behind them and stared at her. Understanding the message the female decided it would be best to do what they said. She sped up her steps and lead the trio of humans and Corvus to a large courtyard the guards apparently trained in.
Corvus began inspecting the area, paying no attention to the gathering equines and making sure to block out the orange one's presence. After examining the courtyard Corvus nodded their head and spoke.

"This will do."

"Do for what pray tell?" Questioned a suspicious Luna.

"Catharsis." Was the answer.
Which elicited a confused "What?" from Rainbow Dash.

"He's going to let out his anger and release some of his power." Beatrice answered.

"How exactly?"

"Training." Replied Corvus

"By that he means beating the shit out of us." Stated Ben as he and the others pulled out their weapons and took up ready positions around Corvus.

"Tier 3. Gencall!" Were the only word Corvus said as they assumed the fluid stance, and with that their three companions rushed at them.p
Corvus leaned out of the path of Trick's charge disk and swung their fist into Ben's face, before twisting away from Walker's daggers. Ducking under a swing from Ben they grabbed his arm and threw him over their shoulder. They then stepped back to avoid a leaping Trick, driving their knee into her gut as she came down. Ben was getting to his feet as Walker charged at Corvus. They let Trick fall to the ground as they rolled away from Walker. As they stood they swung a leg at Ben knocking him to the ground. Trick threw her charge disk at Corvus' back, but they twisted their arm around their torso and caught the explosive disk, their hand easily containing the concussive blast.

"Crap."
Trick only had time to utter that one curse before Corvus pulled back their arm, whipping Trick around into Ben and Walker.

The gathered ponies watched the foals battling not quite willing to interrupt them. They all had their own thoughts about the scene before them.

'What have these foals gone through to have so much talent in battle?'

'What is that thing planning and how does it involve those three foals?'

'I can't wait to learn all of these foals' secrets!'

"The brat's actually pretty good for such a little guy.'

'Something dashing yet not gaudy, dark blue perhaps?'

'Ah'll teach that kid respect for adults.'

'I hope those poor dears don't hurt themselves.'

'This will bring in viewers for sure!'
They were pulled from their thoughts when they heard Corvalius Dakenistaire speak.

"Brute strength is ineffective, a head on assault is not feasible. Think before acting, use your unique abilities and styles."
The grey colt was standing with his hands in his jacket pockets looking at his opponents lying on the ground. In response to his words the three foals stood up and got into different stances. Beatrice Felix was lightly bouncing, balanced on the edges of her deformed hooves with her yoyo swinging behind her. Benjamin Galith was standing straight-backed with his hands at his sides. And Walker Green was in a relaxed stance similar to the one Corvalius Dakenistaire had used.

"Baed wij gencall!" Corvalius Dakenistaire called out.
The foals sprung forward again, Beatrice Felix was flipping through the air never standing in one place more than a second, Benjamin Galith charged forward pressing a vicious assault, and Walker Green was moving in the same fluid-like manner as the grey colt.
Corvalius Dakenistaire flowed around Benjamin Galith's strikes while ducking under Beatrice Felix's sweeping kicks, punches, and yoyo swings, and blocking Walker Green's attacks while returning their own punches. The quartet of foals became a writhing ball of flying limbs.

As Corvus danced around the humans' attacks they analyzed their movements looking for an opening. Ducking under a punch from Trick Corvus stepped back to avoid Ben's knife. As they diverted a punch from Walker they had an idea. Shoving Walker away they ducked under a swing form Ben. Corvus fell to the ground and landed doing the splits. They drew back an arm, the fist gaining a metallic shine, and punched Ben right between the legs. Those watching couldn't help but wince as Ben's eyes widened and he began to tear up. Ben let out a shrill scream and collapsed clutching at his manhood. All of this happening in two seconds.

"I surrender." He gasped out.
Corvus flipped away from a swinging charge disk and landed a few feet away. Before she could react Corvus sprung at her, a blast of air propelling them, and kicked their feet into her back slamming her into the ground. Corvus landed next to Trick and planted a foot on her back.

After a moment of struggling Trick stopped moving and said "You got me."
Corvus backed away from her and turned to face their final opponent. Walker stood on the opposite side of the courtyard watching Corvus.

"Let's see if you've learned anything."
With that the two fighters sprinted at each other. Corvus sidestepped a fist from Walker and grabbed his wrist and threw him over their shoulder. Walker landed on his side and rolled to his feet before charging again. Corvus twisted their body in unnatural ways to avoid the barrage of high-speed punches. Corvus kicked at Walker's stomach only for him to backstep and grab their leg. Walker levered them over his shoulder and Corvus' face impacted the ground.

The observing equines flinched and started to approach the colt, only to back up in shock as he pushed himself up and stood on his hooves looking no worse for the wear.

"You may be skilled in other styles, but you're only a novice in Guanvieloshek."
Corvalius Dakenistaire held out his arm with their palm facing Walker Green. What appeared to be an orb of glass formed in the colt's hand which then filled with white, bright purple, and electric blue energy.

"Charge Bolt." The colt stated.
With that the orb shot out of his hand and flew into Walker Green's chest knocking him to the ground. Corvalius Dakenistaire walked up to the downed colt and looked down at him.

"I submit." The prone colt stated.
With that Corvalius Dakenistaire held up a hand and raised it up lifting the trio of foals to their hooves, seemingly completely uninjured.

"That was fun." Came the voice of Benjamin Galith, causing many of the ponies to wonder how that could be consider fun.

"I need to work on my velocity and trajectory, I should've been so much faster more precise than that." Complained Beatrice Felix, leaving the pegasi and alicorns stunned that the filly's acrobatics were considered slow and imprecise.

Corvalius Dakenistaire then stated "You all did exceedingly well fighting your best under tier 3 restrictions."
It looked like he was going to say more but suddenly his head swiveled towards the way they had all come from and began marching towards the hall shoving past the ponies in his way. The ponies all followed after him, his strangely swift and silent stride necessitating that they quicken to at least a jog. Soon enough they had all arrived back at the medical ward and were awkwardly shuffling through the doorway.
The grey colt walked up to a critically wounded stallion lying writhing in pain on a hospital bed with a heart monitor slowly beeping and removed his sunglasses. He and the stallion looked into each other's eyes for a few seconds and then the stallion smiled and closed his eyes with a nod. Corvalius Dakenistaire took of the glove on his right hand and brushed his hand over the stallion's forehead. The stallion's body stopped moving and the heart monitor went silent.

'WHAT HAST THOU DONE?!' Demanded a furious Princess Luna.
The colt replaced his glove and glasses, turned to her, and spoke two words.

"Freed him."

Author's Note

The full names thing is because the ponies don't know that humans have multiple single word names not a single multiple word name.