Before the events at Ground Zero and for a short time afterwards, Heat is calm and emotionless, efficiently executing Serph's orders. However, once his emotions emerge, he becomes brash, with a strong penchant for violence.

he is unable to act on them because of the odd nature of his emotions: having no experience with issues he could not settle with force has left him with near-to-no experience in dealing with complex feelings such as love and jealousy.