Seryu Ubiquitous
The main antagonist of the anime/manga Akame Ga Kill! is Seryu Ubiquitous. She was a former member of the Imperial Guard and a current member of the military unit known as the Jaegers. Seryu had a strong sense of justice that was distorted, which helped to define her obsessive psychosis. She is Mine's greatest adversary.
Seryu acquired a vicious sense of justice as a result of Captain Ogre, her mentor and superior, and her father, a member of the Imperial Army, dying at the hands of the Revolutionary army. She only holds the opinion that the Revolutionary Army is a band of criminals and the corrupt officials of the Empire are blameless. Seryu was a vicious, insane, and unstable lady, despite her outward appearance of kindness and compassion. She was observed to take great pleasure in murdering persons she viewed as evil, almost as if it were a pastime.
Seryu Ubiquitous had a twisted vision of good and wrong that was almost wholly black and white; he saw the Empire's rule as wholly legitimate while viewing its foes as pure evil. Seryu does not show mercy to people she considers to be criminals. She prefers to kill people in cold blood rather than question them. Seryu altered her body physically with Dr. Stylish's assistance in order to punish the perpetrators.
Anime: Akame Ga Kill!