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Barry is the fastest man alive.

Barry is a hero.

Barry doesn't kill.

Barry can move so fast he can travel through solid objects.

The process can be dangerous and can have terrible consequences.

When he first discovered it, he tried phasing just one finger through a piece of paper.

He could feel himself traveling through it.

Soon he learned to phase through any object.

Once he was traveling so far he phased through a bird accidentally.

He learned he could even phase through living objects.

It's that ability that allowed Barry to phase his arm through the back of Weyland's head.

Barry's index and ring finger appeared to go through eye sockets, the middle through the top of the nose, pinky through the temple and his thumb stuck through the top of the ear.

In an instant Weyland would have died, but Barry kept his hand where it was. The mirror Weyland was standing in front of offered a view Barry normally didn't see when he killed someone. He could see the indifference in his eyes. Weyland's eye's burst, viscous fluid dripped down his cheek. This happened sometimes. If Barry phased through a living object long enough. They stopped feeling instantly, but sometimes Barry needed to see it. 

Many years prior was the first time that Barry learned he could travel back in time. There were many aspects of his speed, but only when going his fastest could he travel outside of the time stream. Like most of his abilities, he did so the first time by accident. Going back a day meant that he took over his older body. Going back further meant he physically went back. He never went back physically if he could help it. Too far back caused too many changes, with side effects that may not even being obvious for years. 

Barry pulled his hand from the inside of Weyland's head. The body collapsed with a thud. Barry shook his arms as fast as he could, splattering the walls of the small apartment with the inside of Weyland. Not that it mattered. The first time Barry phased through a living object he was so distraught he did what he always does to clear his head, run. He ran so fast he was back running an hour earlier and could see the bird. He ducked and slid to a stop. The bird continued on to a tree. 

A woman started banging and yelling at the front door. Sometimes Barry liked to get caught. He was always curious what the reaction was of seeing one of the greatest heroes on the planet standing over a dead body. Rarely did they ever blame him. Every interaction always ended with "I hope you get the guy that did it." Barry didn't feel like an audience. He ran.

Barry ran back to the moment he was about to knock on Weyland's door, and stopped. He looked at his hand, no longer stained with blood and brain matter. The air only smelt like cat piss. 

Barry is the fastest man alive.

Barry is a hero.

Barry doesn't kill.