Post an anime character who is tragic villian

Suigintou from the Rozen Maiden series.

Takasugi Shinsuke from Gintama

~Disowned by his family so he was taken in by a temple school but the school was destroyed and their beloved sensei got taken away during the kansei purge

Got captured during the war and had to watch helplessly as his bestfriend take the life of their beloved sensei to save them, a fact he never wanted to acknowledge. He lost his eye in that moment and the last thing that crushed eye saw was the face of his bestfriend with a sad smile on his face.

He wanted to die that day... he wanted his friend to save their sensei and just leave himself behind to die. Blinded by anger, he points his blade at that man. Claiming that he will destroy everything that man holds dear.

Kabuto was always my favorite Naruto character. But finding out about his past (or lack of thereof) made his descent into darkness more sympathetic

Argue with me if you want, but

Annie Leonhardt (Shingeki no Kyojin)

Itachi Uchiha (Naruto Shippuden)

Airi Yūnami from Qualidea Code
She was an alien with a human guise that initially considered the human children held captive by the Unknown(her race) to be expendable, but began to consider them family the day she began to work with them, and desired to have a child of her own.
In the end, she ended her life at the hands of Maihime Tenkawa, one of the children who looked up to her as a mother figure, to stop the dimensional hole the Unknown used to invade Earth from functioning so that the aliens would not harm Earth or humanity anymore.