Phantom: Requiem for the Phantom is a tV series anime that premiered in spring 2009, produced by Bee Train.

About the production: the story comes from a visual novel, there are 26 episodes of about 24 minutes and its current status is "finished".

Its main genres are action, drama and thriller, with themes such as Amnesia, Anti-Hero, Assassins and Noir.

On AniList, Phantom: Requiem for the Phantom has an average score of 75%, a very good score, and appears on 63,311 users' lists.

A young man wakes up in a strange room with no memory of who he is or how he got there. His past is lost—and his future belongs to Inferno, a violent crime syndicate. They give him a new name—Zwei—and team him with their top assassin, the enigmatic Ein. She’ll teach Zwei all he needs to know about his new life as an Inferno operative, starting with lesson number one: kill or be killed. (Source: Crunchyroll)

Official synopsis from AniList.