Babylon
"Wayvern!" Celestia rushed to him. "How do you fight that!?"
"There's an ancient spirit of gargantuan size able to cut down Kaiju in their second life," Wayvern explained. "If I can summon him, Babylon will have no trouble against Pyrhon."
"What's the catch?" Celestia said, detecting the problem in his voice.
"Babylon needs two hunters to summon it. And they need to be perfectly compatible battle partners. If Avalanche were still alive I could do it, but…"
"I'll help!" A voice said from behind them. Wayvern turned around to find an old friend standing behind them. His hair was red and spiky, like the flames of a forge. Behind his glasses were eyes that glittered a silvery grey, like the iron of an anvil. He was dressed in a Hakama, a traditional Samurai garb, with a Katana's scabbard on his hip. The scabbard itself was empty, but he knew that it could be filled with any mineral and a katana would be made.
"Vulcan!" Wayvern rushed to his friend and high fived him. "What brings you to Equestria?"
"I heard that Relies returned, so I came to help investigate, and also the Universal Council wanted me to keep an eye on you, for security reasons."
"You said that you could help summon this Babylon," Celestia said. "Are you a compatible fighter with my brother?" Vulcan looked at Celestia and gave a look that concerned Wayvern.
"Not Exactly, but Wayvern possesses the memories of every living creature in the universe, or at least every creature in the universe that was alive during his time. I'm sure we can figure something out." Something told Wayvern that was a hint. Then he got the idea.
"You want me to tap into your memories to learn your fighting style?"
"Right!" Vulcan said. "And you better hurry or the Kaiju will burn down your home!" Pyrhon was already headed for Canterlot when Vulcan said this. Wavern had to try the proposal. He focused on his friend hard enough to remember what he could about him. Then he started to remember from his point of view.
"I think I got it!"
"Let's go!" they grabbed each other's hand and raised them over their heads
"We call upon the Colossal Blade and the Spirit Babylon who wields it!" a giant stone warrior dropped out of the sky, pulled a golden sword off his back and prepared to fight Pyrhon. Pyrhon noticed Babylon, and pulled out a flaming sword. At first Babylon had trouble attacking Pyrhon with his attacks phasing through the flames, but eventually, he managed to land a hit in the eye.
"You wanna do the Honors, Wayvern?" Vulcan asked.
"Got it! Pulse Blast!" a vibration of the sword later and Pyrhon exploded.