Luna walked alongside her friends as they climbed the stairs leading to the fortress's front doors. They had passed the gates without difficulty, suffering only the gaze of the red-eyed shades stationed atop the walls. The undead stood unmoving, silent and unnerving in their eternal vigil. Luna wanted to scream at them to do something other than stare, but she knew that there were better uses of her energy.

"Well, at least we've had lots of excitement," Cadance said. She was smiling in spite of their awful situation and the pulsating evil aura at the center of the fortress.

"Yes, there has been lots of excitement," Celestia said as a smile formed on her own face. The clopping of their hooves on the black stone stairs of the fortress echoed through the eerie, perpetual twilight of the Wasteland only to be offset by the growing cheer of the two princesses.

"We've been so focused up 'till now, and suddenly the two of you are smiling?" Luna said as she watched her friends. "We're facing certain death in a way more horrible than anything Octaria could have offered!"

"And yet," Cadance said as the doors opened before them. "I feel no fear, only excitement. It's as if this journey to face Dark Arceus has been nothing more than an amusement park ride, terrifying at first, but curiously exhilarating once it comes time to confront it. Especially when we've already done it once before."

"As insane as that sounds, I'm inclined to agree," Celestia said as they were greeted by two Kyurem standing guard just past the entrance. Another pair of shadowy Kyurem watched the ponies from down the long, somber hallway before a second set of brass doors.

"I suppose when one fights evil on a nightly basis, such things are viewed through a different lens," Luna said as she looked at the ice dragons with disdain.

"Ah, yes, nightmares can be terrifying," Celestia said, her tone joking and exaggerated. "Elder ponies looking for their lost horseshoes, clouds that look like the dreamer's sister, and cutie marks! Why, the fears of fillies are just the worst, aren't they?"

"You make it seem paltry when you put it that way," Luna said, angrily. "Fillies aren't the only ones who have nightmares, you know."

"Oh, it's just a joke, Luna. Lighten up a bit!"

"Light is your domain. I prefer dark humor," Luna said as she turned to a nearby Kyurem. "For example, why did the dragon-type cross the road?"

The shade stood silent and menacing. It's red eyes narrowed as it watched the princess.

"I don't know," Cadance offered. "Why did the dragon-type cross the road?"

"It was running from an evil Togepi that wanted to kill it!"

The shade growled its displeasure, but continued to watch the ponies.

"You should work on your jokes," Celestia said, with a slight grimace. "Who would believe that a sweet, little Togepi could be evil? Much less kill something!"

"Perhaps it got up on the wrong side of the bed?" Luna offered. Celestia sniggered at the remark.

"Perhaps observational comedy is more your forte, Luna?" Cadance said, kindly as Luna turned her nose up. Though she and Luna soon joined Celestia in her laughter.

"I'm still working on my jokes," Luna said, happily as she turned to face the doors. "And Pinkie Pie seems to think observational humor would be a good direction, as well."

The ponies watched as the doors to the throne room opened at their arrival. They walked through, their wings outstretched and their horns glowing with magic. An angry grey fist greeted them, held out before a familiar form. The fist came down, and suddenly the princesses found themselves pummeled by wave after wave of psychic force, as if a giant hammer was attempting to beat them to a pulp. After the third wave, the ponies teleported out of the newly formed crater and charged their attacker.

Mewtwo had already assumed his Mega X form, and he quickly took the fight to the ponies. He assaulted the princesses with vicious kicks and tail flips, slamming Celestia and Luna into the northern wall. Cadance dodged his first attacks, firing beams of destructive magic that crackled with power as they flew through the air. Dodging her attacks as he closed in, Mewtwo began throwing Psycho Cuts at her neck with brutal precision. Each strike landed on the same spot on her shield, reinforced by all of Mewtwo's hatred. Surprise almost froze the princess, but instinct kicked in first, and Cadance teleported away. Mewtwo followed her, even as she continued teleporting around the throne room. She couldn't outrun him, and despite her best efforts she couldn't land more than a glancing blow with her magic. Luna and Celestia appeared at Mewtwo's sides to attack him with wing, hoof, and horn. He dodged, blocked, or simply absorbed all of the punishment, never stopping his own assault on the youngest princess.

Finally, Cadance's shield broke at the point just above her jugular vein. She teleported once more in an attempt to escape Mewtwo's next strike, but she was a moment too slow and he grazed her neck before she vanished. She held the cut with one hoof, as Mewtwo materialized above her. Celestia intercepted his attack as he went for the kill, teleporting between the fighters to block his Psycho Cut with her body. The force sent her flying into Cadance, and the two skidded across the floor several yards before stopping.

Luna appeared at Mewtwo's side before he could launch his next attack. She grabbed the Pokémon with her magic and threw him hard into the wall where she and her sister had crashed moments before. Mewtwo teleported upon impact, appearing above Princess Luna to launch another series of precisely aimed Psycho Cuts. Knowing she couldn't outrun him, and furious over Cadance's injury, the Princess of the Night entered close combat with Mewtwo.

They traded blows, her wings and hooves beating against his Barrier just as harmlessly as his punches and kicks beat on her armor's shield. Out of the corner of her eye Luna saw Celestia looking after Cadance, who seemed desperate to return to battle. Mewtwo noticed this, as well, and his bloodlust rose at the sight. As Luna kicked at Mewtwo's head once more, he teleported away, appearing directly above Cadance. Another vicious Psycho Cut was launched at the pink pony, only to be blocked once more by Celestia. The elder princess took the full brunt of the attack, her wings outstretched as she dug her hooves into the stone floor to keep from being thrown again. With a cry she teleported to her foe's side and fired a massive beam of destructive magic. Propelled by her fury, she had reacted with shocking speed, and all the Pokémon could do was cross his arms and absorb the blast as it washed over him and tore open the side of the fortress.

Cadance was on him before the smoke had cleared, beating him with her wings and throwing bolts of lighting from the tip of her horn. His Light Screen had taken most of the damage from their spells, and his Barrier took the brunt of their physical assaults, but these protections were quickly running out. The princesses knew this. They only had to buy enough time to wear him down.

Cadance dodged with a speed and grace that Mewtwo had thought impossible of her. She was driven by more than a will to survive. She wanted to win. With a scream of rage, he stepped up his attacks and she was quickly forced backwards. He grabbed her and threw her, only for her to teleport a moment before making contact with the wall. She appeared some yards from him, panting heavily as she charged her horn with magic.

Exhausted, Mewtwo took a single, deep breath as he prepared to teleport to Cadance's side and continue his assault. As he exhaled, he felt a tightness wrap around him like chains. The Pokémon roared in impotent rage, frozen in mid-air, held firmly by Princess Celestia's magic. He fought to free himself, but the princess held him tightly. The chains had expanded into a magic bubble that was now stretched over his body, constricting his movement and trapping his power.

"You've bitten off more than you can chew," Princess Celestia said, sternly. "Give up, Mewtwo. We've fought on your terms thus far, but if we have to turn you into a squirrel to get you under control, we will."

"I refuse to bow before you!" Mewtwo shouted as Cadance and Luna came to stand beside Celestia.

"We never asked you to!" Cadance said as she began channeling a spell to heal the cut on her neck. "All we want is to protect our friends and family. God's Breath has become both."

"You have no right to rule! You have no place above the council!"

"Our place was not decided by us," Luna said. "It was decided by fate, and the king who sent you to us. We rule God's Breath now out of necessity."

"Siebold was a fool!" Mewtwo shouted as he struggled to force his way out of the spell holding him. Celestia's grip was too much, however, and it only tightened as he fought until he couldn't even open his eyes.

"He seems rather wise to me," Celestia said, calmly. She appeared to be holding Mewtwo so easily, and that only served to enrage him further.

"You idiot!" he said, his hatred and panic bubbling to the surface with such force that he was no longer sure of his words. Still, they came, and with them a feeling of truth. "I have felt the dark god's power touch my mind. You can't fight Dark Arceus! It will break free, and turn everything to bone and ash!"

"It sounds as if you've given up," Cadance said, sadly. "The Mew defeated Dark Arceus once…"

"And it cost them their entire species!"

"Yet the survivors never gave up. They're your ancestors aren't they? Why do you forsake their purpose?"

"Because I have seen the truth," Mewtwo said. The moment he spoke those words a splinter of hopelessness struck his heart. A painful realization overcame him, then, one that he felt he had known all along.

As Mewtwo struggled against Celestia's magic, he built up his psychic power until it felt like he would burst. Now, as the alicorns began discussing how they would return him to the city, he let loose his might.

The entire fortress shook as he unleashed a massive wave of psychic energy upon the ponies. The walls cracked, the floor shattered, and the ceiling was opened to the sky. The twelve floors above their heads were decimated as Mewtwo's rage poured out over everything around him. Celestia and Luna leapt to cover Cadance, raising magical barriers as they placed their bodies between her and Mewtwo's sudden assault. When the attack had ended, their shields had been shattered. Their armor was broken, cut and dented, their wings scorched, but Cadance had been unharmed. Panting, the princesses rose from their huddle to watch as Mewtwo opened a portal before them.

"I am unworthy of my ancestors sacrifice by the mere fact of my birth," Mewtwo panted as he drew the prison of Dark Arceus to him. He looked to it, and then to the ponies. "Let us see if you are more worthy than I."

Without a second thought, he threw himself, and the prison, through the portal as the ponies limped after him.

"What now?" Cadance asked as she stared through the raging current of lacerated space-time.

"We follow him," Luna said. She coughed, and nearly fell as she began walking toward the portal. Celestia and Cadance ran to her sides, holding her up as she struggled to keep her balance. The shadowy Kyurem watched them, unmoved and unharmed by the assault that had shaken the foundations of their master's sanctuary.

"Why haven't they attacked us yet?" Celestia asked, as she stared warily at the four sentries.

"Their master hasn't willed them to…"

"No time to worry about that," Cadance said as she cast a quick healing spell over her friends. Their wounds were lessened slightly, and a bit of strength returned to them. The ponies steeled their resolve as they approached the portal, and as one, they charged into the unknown.