AN: Hey, ya'll~ It's me, the infamous author who starts more stories than she finishes. This time, I'm pretty pumped for this fanfic, so hopefully I'll be consistent with updates. Hahaha…

Anyways, this AU takes place in the movie just after the group had knocked Yokai to the ground and the mask slid across the ground. I don't remember the exact movie dialogue or remember every tiny little detail, so please bear with me if I get anything wrong, even though I'm not completely going with the storyline after the first fight scene. Thank you~

I've decided to just get into the AU instead of just rewriting the whole scene. So, here you go! Hope ya'll enjoy, since I'm not exactly the best writer, and the next chapter will be here soon.

He's down!

Hiro lunged forward, snatching the mask off of the floor swiftly and then jumping back from the stirring figure on the cold ground. He panted slightly from exhaustion as everything that had just happened slowly processed in his mind.

Their plan had worked.

Their plan had actually worked!

Buzzing with anticipation, Hiro backed up to where Baymax had flown down to join him. He smirked darkly at the healthcare robot. "We got him, Bay…" he said, grinning. "Now I can finally see who's responsible for Tadashi's death…"

The others had begun to gather behind the young prodigy, bitterly curious as to who had caused them so much pain in the past month. They were all determined to fight at that moment; to bring justice in the name of the one person who shouldn't have passed when he did.

"Stand up," Hiro demanded suddenly, clutching the mask tightly in his grasp as he glared at the one on the floor. "Stand up and face us!" Gogo, Wasabi, Fred, and Honey all turned their heads to see how the older man would respond.

Chilling, cold laughter followed Hiro's sharp words, instantly sending shivers down the spine of everyone in the room.

"You just couldn't leave well enough alone, huh, kid?"

Hiro's heart lurched as the familiar voice echoed around the once-proud laboratory. The messy-haired boy felt his knees go weak and he suddenly found it very difficult to breathe as he struggled to remain upright. "U-Unbelievable…" he squeaked, shaking his head slightly as he backed up even further away. He clutched the mask close to his chest as the figure stood to his full height, and when he turned around and his friends involuntarily gasped, Hiro's worst fear was confirmed.

Standing in front of them, with awful burns covering parts of his face, was none other than his supposedly-dead sibling, Tadashi.

Hiro felt like he was going to hurl.

"You're pretty stupid; all of you." Tadashi grinned sadistically, the burns on his face a constant, unsettling reminder of what led them to this moment. "You didn't have to be a part of this. You didn't have to get involved in my business. You'd all still be safe at home if it weren't for you meddling where you shouldn't have."

"No way…" Gogo breathed after he had finished degrading them. She shook her head in disbelief, hurrying forward and standing in front of Hiro protectively as she brushed his cruel words off. "No. You're dead. Hiro saw you die. You're dead! This has to be some sort of trick!"

Tadashi had perished in the explosion along with Professor Callaghan.

There was no way he could've survived that.

"..." Tadashi's good eye was suddenly drawn to the boy behind her as soon as she uttered to name, 'Hiro'; his other eye was nearly shut and gray with newfound blindness as a result of the explosion.

Gogo's words flew right over his head as he studied the shaking figure across from him.

"Hiro…" he murmured, his eyebrows furrowed as if he was struggling to remember something. How did he know that the name belonged to the child? But the recollection was gone as soon as it came and his mouth quickly twisted back into a sick smile as the short girl's words came rushing back to him.

"Do I look dead to you, sweetheart?" came his rude reply. Gogo frowned and simply glared as Honey cautiously spoke up next.

"Tadashi… what happened to you…?!" she whispered. Wasabi and Fred continued to watch the scene play out, still frozen from shock.

"...Tadashi?" replied the other after a few seconds. "I haven't the slightest idea of who that is." This immediately infuriated Hiro, who pushed his way past Gogo and took a few daring steps towards his brother, tears barely shining in his conflicted brown eyes as he stared the other down.

This wasn't Tadashi.

"How dare you?!" he screamed, his gloved hands balling into tight fists. "How dare you run into that damn building?! How dare you say you don't know your own name?! How dare you steal my microbots and leave me to be eaten alive by depression?!" The tears were free-falling now and Hiro couldn't care less if he was making an unnecessary big scene.

Although it wasn't very 'unnecessary', considering the young boy just found out his 'used-to-be-dead' brother was alive and wrecking havoc with his stolen microbots.

Oh, Hiro was seething with fury and heartbreak.

This couldn't be Tadashi.

"You ran into that building," he hissed through gritted teeth in a low voice. "You left us…" Hiro's voice cracked and he suddenly felt all of the anger leave his body and replace itself with misery. "You left me… alone…"

Tadashi wouldn't do this to him.

Meanwhile, Tadashi simply stared at Hiro as he was breaking down. The older teen found it oddly… funny that he such a big effect on the small boy as a result of the mask coming off. He frowned a bit as the other continued to rant, blocking him out as he thought to himself.

Tadashi didn't have any recollection of his life before him…

Could this boy, Hiro, have something to do with it?

And then suddenly, without warning, Tadashi desired to have Hiro.

He wanted to know more about this boy; why he was so upset, why he was spewing such nonsense, his secrets, the knowledge that was stored within him.

Tadashi wanted Hiro within his possession.

And nothing was going to get in the way of him achieving that goal.

Baymax looked at Hiro. "Your neurological senses are unstable. Perhaps you should exclude yourself from social activities for a bit." The robotics prodigy ignored the robot and continued to glare daggers at his brother through his tears.

He was my best friend.

My hero.

My brother.

I will never forgive him for the pain he put me through.

"So, Tadashi…" Hiro growled after he had calmed down. His friends exchanged awkward, conflicted glances with each other. "You're going to come home and you're going get your life back in check, because I know. I know this isn't you…" Hiro shook his head, taking another step closer to him. "I know my brother is still in that criminally insane mind and I'm going to get him back, no matter what it takes…"

I might never forgive him.

But I won't give up on him.

Hiro then turned around to face his robot friend. "Baymax, get us out of here-"

"HIRO!"

The fourteen-year-old blinked and before he knew it, the mask was being ripped out of his grasp and he was being pinned down by a swarm of microbots. When reality finally caught up to him, Hiro began to struggle against the very invention that started this whole mess. "T-Tadashi!" he snarled. "L-Let me go!" He then looked up to see that his teammates, including Baymax, were in the same position. "Let them go too!"

A shadow fell over him, causing Hiro's head to snap up and his eyes to widen at the sight of his masked brother towering over his defenseless being.

"You're mine now, Hiro."

Everything went black.

AN/2: Again, hope you somewhat enjoyed it. I'm sorry if things are moving too fast, I'll try to slow them down in the future. Thanks for reading. :)