Revenge

After escaping from a mental hospital, deformed Naoko goes out with a pumpkin on her head to hunt/kill those who bullied her in the past

Wataru attempts to avenge his dead sister's rapist/killers who were protected under the Juvenile Act, after being run over by them he gains the ability to manipulate others by going into people's dreams. Knowing that his ability allows him to do a "perfect crime," he vows to avenge his sister... when night falls.

Title is self explanatory. The law handles criminals poorly so detective Kim Ji Yong becomes a vigilante to target them.

Ryuuzaki Ikuo and Tatsuya Danno witness their teacher Yuiko’s murder and testify that a man shot her, but they were told to keep quite while the police cover up the incident. 15 years forward one is a detective and the other a yakuza member, both work together with a motive to avenge Yuiko’s death.

After his father and teacher get murdered by the 'Castle' organization, Kim Shin becomes a killer for revenge.

Shou is a vigilante trying to straighten corrupt in the Japanese government through terrorism with his "One man, One kill" code of action. Heavy on politics.

Homicide detective Hiroki Dan takes on a secret identity to go after criminals and perpetrators….
dude making his pottery every time he kills got me thinking its made from the ashes.

This list is inspired by this manga.

Is it okay to kill people? when five bullies has taken away everything from him,"I won't let anyone take this revenge away from me" Shin Uruma swears and gets trained by his grandpa

Aizawa was bullied by Suzuki to the point he dropped out. 20 years later in a reunion Suzuki says "the one who gets bullied is the one to blame" then Aizawa picks himself up to become a teacher, teacher of Suzuki's daughter who is bullied by others "could you say the same thing now that your own daughter is getting bullied" he thought. What will Aizawa do with this situation?