Your Lie In April: Across The Multiverse

Prologue

Dr. Doom clenched his fists as the power of the Infinity Stones bathed every vein, every muscle, and every tendon in his body, in uncontested power. The glow radiating from his titanium armor matched his hubris, and his dark green cape flapped behind him as he hovered around this strange "Overlook" dimension between all universes. With his desire to attain absolute supremacy fulfilled, one would think that the mighty Victor Von Doom would be satisfied with the fill of blood he'd just had from beating The Watcher in a head-on altercation.

But no.

The tyrannical despot wanted more.

Feasting his eyes upon his new targets, Doom pondered which universe, out of this collection of many, he should conquer first. The multiversal gateway dimension glistened around him like a giant mirror. Except in this mirror, every shard of "glass" was really a window into a unique timeline, teeming with life and conflict. 

Doom wanted it all.

But where was he to start?

Reaching out with the Mind, Soul, and Reality stones, Doom began his search for a suitable puppet to aid in his conquest of the Multiverse. If no one in the now-annihilated timeline he once called home would listen to him, then perhaps the others would. 

At first, his search across the minds and souls of life forms spanning thousands of timelines bore no fruit. 

Then Doom stopped.

He smiled.

Yes, this man would make an ideal puppet for his first conquest. What was his name, this bitter, insane man who could transform into a fifteen-meter hulking instrument of death? Ah, there it was.

Eren Yeager.

After pinpointing the correct entry point among the countless glass windows, Doom utilized the Space Stone to teleport his way in. He cared not for his old universe that had rejected his rule. All traces of the life that had defied him had been annihilated during his purging of resistance to his reign.

Or so he thought.

While Dr. Doom was making his way into the universe of this Eren Yeager fellow, something stirred. 

No, someone.

Back on Doom's home planet Earth in the empty universe, not everyone had been eliminated by the fallout of his victory. For in one lone fallout shelter, on the island nation of Japan, a lone boy slept restlessly in his underground refuge.

A dark-haired, blue-eyed boy whose name had been known by every single young musician in Tokyo.

A boy whose skill at the piano was unmatched, even when compared to that of the great Classical titans.

A boy who was now confined to torturous solitude, doomed to suffer this monumental loss without the aid of his friends and family...

Kousei Arima. 

.............................................

The Watcher walked into the meeting room set up by Strange Supreme, and smiled at the sorcerer's talent for design.

"A pub?" he asked.

"Read about it in Captain Carter's biography," Strange Supreme answered. "Figured it would be an appropriate choice. I'm assuming the rest of the team has been selected?"

"Not yet," the Watcher said. "There are a few more who I need."

"Alright then," Stephen Strange said, rubbing his hands together. "Let's do another search, shall we?"

Opening the map of the timelines, Strange Supreme allowed the Watcher to inspect them before making his selection. At first, the Watcher did nothing. Then, he pointed to the timeline where Doom had come from.

"There. That one."

"Huh? But I thought Doom destroyed everything there."

"Not everything," the Watcher said. "Let alone everyone."

The Watcher zoomed in on the barren universe, putting Earth into focus. As he'd hoped, the last member he needed for this mission was still there.

The other Guardians had been selected to solve the combat aspect of the mission.

This young man would solve what would come after.

For this boy was no ordinary boy.

"Him?" Strange Supreme scratched his head. "But why?"

"It will take more than warriors superior in strength to stop Doom's plan, Stephen," the Watcher foretold. "Without this boy, the universe Doom threatens will never be truly saved. He has something else we need, something just as crucial as power and courage."

The Watcher paused, gazing at Kousei's visage displayed in the window to his universe.

"His resilience, his music...and his empathetic heart."