Mello

Mello( Real name: Miheal Keehl is one of the two successors of l and a major antagonist in death note, although not truly evil, his methods of capturing Kira are downright insane and ruthless, down to the point where he even kills innocent people.

Summary
Mellow was one of the people who grew up in the wammy house along with near, he was meant to be a successor and wanted to avenge l when he heard of his death. After it was announced that l never chose who, he was told to work with near to find out the truth about Kira. However, he refused as he did not want to work with anyone else and wanted to solve it on his own.