Impmon

Impmon is a Rookie-level Digimon, partnered with Ai and Mako Terada. His history is one of the most complicated of the group. He used to be one of the Seven Great Demon Lords, but then he mysteriously disappeared and returned as Impmon with no memory of his past whatsoever. He proceeded to befriend to human children, but their selfish actions regarding him eventually led to him leaving them in disgust, now full of contempt for the human race and any Digimon that associated with them. He was frustrated that he couldn't digivolve like the others. Eventually he made a deal with the Deva Caturamon, and became Beelzemon. He promptly tried to kill the Tamers and their Digimon, succeeding in killing and absorbing one, until he was beaten by Gallantmon. However, the Tamer of the destroyed Digimon, Jeri, made Gallantmon spare his life. Now seeing the generosity of humans, Impmon sought out his old friends and became their partner. He proceeded to help the others against the D-Reaper to make up for past mistakes. His known digivolutions are Beelzemon and Beelzemon Blast Mode.

When Impmon hated humans, he was a loudmouth and a bully, getting his kicks from picking on weaker Digimon like Calumon, insulting others and scaring humans with his Bada Boom attack at night. However, this was mostly a front, as in reality he was a little wretch that wanted to get stronger by any means necessary. His nicknames included "Pineapple-head" for Guilmon, "Cream-puff" for Calumon, "Helicopter-head" for Terriermon and "Fox-face" for Renamon. As Beelzemon, he relished the fear he inspired in other beings, but when Jeri spared his life, he became consumed by guilt, and from then on, he did his best to protect the Tamers and their Digimon, and Jeri in particular.