Mihael Keehl (Japanese: ミハエル・ケール, Hepburn: Mihaeru Kēru), universally referred to by the mononym Mello (メロ, Mero), is a fictional character in the manga series Death Note, created by Tsugumi Ohba and Takeshi Obata.

The character of Mello was created, along with Near, to break the endless cycle of confrontations between the detective L and Light Yagami, the man behind the persona Kira.

Mello, whose real name is Mihael Keehl, grew up in Wammy's House, an orphanage for intellectually gifted children, and is one of two potential successors to L—the best detective in the world.

When L dies, it is proposed to him to work with Near, the other potential successor, to find L's murderer, a criminal dubbed "Kira".

Sidoh reveals to him—in exchange for some of Mello's chocolate—that there are two extra fake rules (in addition to a number of real ones specified to each Death Note's owner).

Mello begins to theorize that whoever Kira is, he probably used these spurious rules to fool the Japanese police into thinking he is innocent.

In order to escape, Mello detonates remote-controlled explosives, after one of his Mafia accomplices fatally wounds Soichiro.

Mello is left with a scar on his face, and the failure of his Mafia scheme leaves his real name in Light's hands.

However, Takada uses a hidden piece of Death Note paper to kill Mello, as Light had told her his name and what to do in such a situation.

[13] Mello's actions ultimately lead to Light's downfall; Teru Mikami uses the hidden real Death Note to try to kill Takada, which leads to Near learning that the notebook Mikami had been using prior is fake and swapping the real Death Note with his own fake for the final confrontation with Kira.

Mello takes Himura's help to kidnap Sayu Yagami in order to obtain the Death Note.

[17] Light Yagami makes Himura blow up Mello's hideout with the help of Death Note.

[23] Tsugumi Ohba, Death Note's writer, introduced Near and Mello together because he felt L individually could not defeat Kira and that introducing only one new character would produce a "repeat" of the struggle between Light and L. Ohba asked Takeshi Obata, artist of the series, to make both characters look "a little 'L-ish.'"

Referring to Mello and Near's introduction, Julie Rosato of Mania.com said the "focus on both makes for a clash of attitudes and rough transitions".

[36] Erin Finnegan from Pop Culture Shock praised Death Note: The Last Name for the absence of Mello and Near.

[48] By the ninth episode, Bridges commended how Mello was developed into an "integral part of things and a much more threatening presence" in the drama in comparison to his "clear side-antagonist" role in the manga.

Bridges commented that originally he was dedicated to creating his own method to capture Kira, while in the TV show he looks more like Ryuk considering his "guns blazing" attitude.