A hero of justice [My hero academia x Shirou Emiya]

The start of the true journey

Arriving at the building that stain left for him Shirou opened the door and walked inside. A modest home with 3 bedrooms, it was in a forest away from the rest of society. Stain must have used this as a base not long ago. "It's better I check this house for safety before hand."

Trace on!

Scanning the house he looked though it's design. There wasn't any traps of the sort and it was perfectly safe. He needed to be prepared for UA. It was going to be difficult especially with Momo after him all the time. Opening his phone he blocked his family from his contacts and messaged Aizawa. "Hey sir! I've just moved, my new address is ********** please can you send me the UA uniform here." Shirou message Aizawa and went to bed.

Tomorrow

Waking up Shirou walked downstairs and prepared himself breakfast. His heavenly cooking is a very useful skill. Even when making nothing but cereal. Looking down at his phone he saw Aizawas text. "Sure." Simple and blunt.

After putting on a hoodie and concealing his face he walked outside and began his daily walk. Even if he was on the run from his parents that wouldn't stop him from helping others. Moving without sound he jumped across buildings looking for those who would need help. He no longer had the luxury of strolling the streets, especially with his family looking for him.

Watching from above an alley he sees a woman with bright red hair. Her menacing grin stretching across her face as the man beneath her foot screamed for help. "It's so fun to hear you scream! Let's see how loud you scream when I do this!" The girl laughs and summons a red and black orb in her hands. It's ominous element shakes the family man to his core. It even surprises Shirou who was watching and waiting for the correct time to jump in. He knew who this person was, one of Momos best friends. Yua. A sadist with the quirk reverse.

Reverse causes your body's inner healing to move in opposite, this causes your body to destroy itself. It's a dangerous quirk for someone like Shirou who owns Avalon. If this quirk hits him the sheath in his body will rip him to pieces. He has to be careful. Trace On! A sword appears in his right hand. A beautiful white weapon synonymous with the existence of yin and yang. It's name is Bakuya.

Dropping from the sky in complete silence Shirou fell upon Yua to knock her out in one attack. He may have been silent but that didn't stop the victims gaze from revealing his location. Yua instant turns to see what her victim was looking at barely in time to see the black hoodie wearing Shirou. In a panic she shoots her quirk. Reversal!. Shirou swings Bakuya though the air cutting the quirk in Twain and with one swing of his arm. Knocked her out.

But just cutting the quirk in half wasn't enough to save him as it soon activated. Avalon became his enemy as his body began to pull itself inside out. He falls over and screams in pain as he spits up his lungs. His mind flashes inside out. Every second his vision changes as he enters and leaves his mind scape in rapid succession.

All seems lost but luckily the person he saved was one Mr. Shimano. His quirk cell activation was able to act just in time. Luckily Shirou has type B blood as that's the only type he can effect. But due to the effect of reversal, his quirk caused his cells to deactivate! This is just what Shirou needed though as the cells that had been reversing his body were destroyed due to his quirk.

Finally Avalon could activate properly again and it's effects slowly took hold. Shirou still fell unconscious however. The pain of his entire body being ripped apart was to much for the new hero to handle...

Picking up his savior Mr Shimano began the track to the nearest hospital. Shirou saved him and now it was his turn to repay the favor.
Arriving at the hospital Shirou was placed in the emergency ward. They immediately called the person who was his emergency contact in his phone. Aizawa. With minutes he was there asking questions and panicking. He was scared for his future student. Having such a heroic child die would be a great waste.