Anger
Jack was giving Archhaven all he's got. Billy, on the other hand, was holding back so as to not destroy the Sora Tree. Archhaven was just about to perish for the last time, being blasted by the equivalent of 12,345.6 hurricanes. This was, of course, a calculation done in Billy's head, as he shot massive shards of ice through the demon king's chest. In the midst of calculating how much longer until his enemy was dead, he felt a dull pain in his chest. Like filling a cavity, how you feel something happening, but you don't really feel it.
He looked down. A sword blade was protruding from his chest. There was no hilt in sight, so he must have been stabbed from behind. He grabbed the sides of the blades and slowly pushed it back, being careful not to cause more damage. He fell a good 57.3 feet, subconsciously calculating it out of habit. As he landed he scorpioned (which is when you heels go over your head whilst you are face down), and he soon heard a crack, which was his spine. The world started to fade. The last thing he thought he would hear was the beating of his heart.
Which was still working.
This was his chance. Whoever had stabbed him from behind missed his heart, there was still hope!
He concentrated as hard as he could on his wounds. A thin golden line started to move up his legs, behind it his bright red armor turned into a black, purple, and gold combination. He felt his wrinkles vanishing, which was slightly disorienting, since he wasn't used to his skin being so tight. As it reached his face, his missing eye grew back and his other one regained sight, and both went from green to grey. The line passed over his white hair, turning it black with only a small amount of salt and pepper (extremely limited grey hair).
He got up slowly from where he lay. He had rejuvenated many times before, but the age difference wasn't so great in hundreds of years, before he even came to the forest! The power he felt flowing through him was like an inferno burning inside every part of his body.
No... That's not power. I know what power feels like and this isn't it. Then he remembered what this was. This was an emotion he hadn't felt since the fires of Pompeii. Anger.
For those of you behind the fourth wall who don't know, Rule number one: The Doctor lies. Rule number two: Never piss off a mage.
Billy turned to face his attacker, which was Archhaven's small assistant. It was a frog-like creature about two and a half feet in height. "Alright you short little shit, you think it's fun to die? Let me show you how wrong you are," With that, Billy, with his mind, caused the poor creature to burst into a green flame, called Pyrus Acidium. The name says it all.
Out of the corner of his eye, he saw Jack getting mauled by Archhaven. He couldn't let this happen. Jack was young and still had a universe to see. Billy, well, Billy is an old man who truly has nothing left to live for. He had made his decision. He and Archhaven will be sealed inside the astral plane for all of eternity. At least then every man, woman, and child on Earth can sleep easy, even if they never knew the threat that hangs over their heads every day.
He took a deep breath. The air around him would kill a normal person if they inhaled it, thanks to all the magical feedback created by the battle. This spell, thankfully, required a ton of it. Golden figures grabbed himself and Archhaven by the wrists, guiding them to the next plane of reality. Archhaven, being a belligerent cretin as usual, tried to fight. To no avail, of course, these creatures were the truth behind God.
Billy dreamed as he was traveling between dimensions. He dreamed of his first conscious moment, wandering a field looking for his older brother, Andrew. He dreamed of swimming in the murky, almost black pond that started it all. He dreamed his own village being burned by some demonic creature. He dreamed of being raised in the dwarven orphanage, where he swallowed the magical gem that kept him pure. He remembered his first day at the forest. He remembered defending it from what his brother had become. He dreamed of his death as a demon, and second death as a human mage. Then he remembered Hannah, and Tyler. He had left his family without so much as a second thought...
Billy took several deep breath, as if he had held his breath for a whole minute against his will. A purple unicorn was standing above him. That's weird... my whole arm is asleep! He had no idea how to maintain a constant thought process at this point, as was a side effect of inter-plane travel. In a moments passing he went from sleeping body parts to a spray cheese moon. Thankfully, his thoughts were getting longer and more complex, so he could at last comprehend the oddly colored unicorn.
"You're not supposed to exist. This is the astral plane. Nothing is supposed to be here." he already felt his thoughts drifting, he wondered if everything was purple here.
The unicorn responded, or she seemed to be, in Billy's delusional mind "Doc, I think he's a primitive from another plane that got caught in some kind of rift. He seems to think hes in the 'astral plane'"
That certainly awoke Billy's brain, because the bed sheets (that he thought was grass) was up in flames in an instant "Don't you DARE call me primitive! I just single-handedly ripped a hole in space and time to get to no-man's-land and you call me primitive!? I just fucking died and I don't need some bitch calling me simple-minded! He got out of bed and stormed down the hallway and out the hospital doors, leaving, of course, lethal electricity in the air behind him.
"Did that unicorn just talk?"