Mello is one of L's two successors raised at Wammys House, an orphanage for gifted children located in Winchester, England. When it was decided that he should work alongside Near, his fellow successor, Mello refused, citing a personal inability to collaborate with Near due to their differing personalities. Despite having an excellent mind, Mello is known for allowing his emotions to cloud his judgment at times. This emotional instability led to the development of a flaw in his personality that caused him great animosity towards Near.
While not entirely evil, Mello has been shown to have some negative tendencies. For example, he apologized to Matt and showed genuine concern for his well-being. However, this does not detract from his overall darker nature.
Mello's name is unique in that it doesn't actually stand for anything specific. In contrast, Near's name stands for Nate River, which gives some insight into his character and background.
In the Japanese anime version of Death Note, Mello is voiced by Nozomu Sasaki, while David Hurtwitz provides his English dub voice. Javier Olguín voices him in the Latin Spanish dub.
Mello decides to find Kira his own way by joining the Mafia. After obtaining one of the Death Notes from the Kira investigation team by kidnapping Say
Mello is the narrator of the spinoff novel Death Note - Another Note: The Los Angeles BB Murder Cases.