Nagi Taira

One of the strongest people in the world thanks to a special power that converts any murderous intent directed towards him into physical strength and regeneration. Currently bound to a wheelchair.
When his little sister Shizuka was kidnapped he easily slaughtered her kidnappers and saved her. However one of the kidnappers, with his dying breath, directed his gun towards Shizuka. Nagi was forced to take the shot to protect her. The bullet ended up lodged in his skull, rendering him a comatose paraplegic.