Fire

It would be expected due to the trauma that Renji went through, during childhood...that he would not like fire. Now its not to say that he is afraid of a torch, or anything like that, but if there is a fire burning too close to him, and a big one that fills the room. He might fall back into a relapse of the haunting memories of his childhood...listening to his mother scream as the flesh was being burned from her body. And his family's death.