This villain from Hokuto no Ken already has PE category, but needs approval.
What's The Work
The work is Fist of the North Star (aka Hokuto no Ken), a manga and anime about Kenshiro travelling in a post-apocalyptic world.
Who is the Candidate? What He Did?
Amiba was a young martial arts prodigy, he trained in the martial arts, Nanto Suichō Ken with Rei, but he was not chosen as successor leading to Amiba to leave and seek out his fame elsewhere. When Amiba arrived to the village of Miracles, he saw how Toki was able to heal others with his use of Hokuto Shin Ken and was revered as a messiah.
Seeking to learn Hokuto Shin Ken and become famous, Amiba approached Toki to teach him the martial art, but Toki politely refused to share his knowledge with Amiba due to the vows of Hokuto Shin Ken necessitating his silence. Angered, Amiba resolved to figure out the martial art himself and prove his genius to the world. The Cocky Amiba, eager to prove his skill over, Toki, insisted on healing an elderly man villager who he almost killied in his experiments. This caused Toki to intervene, rushing past Amiba and easing the old man's injuries, accidentally lightly brushing his hand against Amiba's face when running by him. Furious by this and all of the praise towards Toki, Amiba subsequently swore revenge on both Toki and the Village of Miracles.
Later he teamed up with Jagi, who helped make Amiba resemble Toki and even scarred his back with a club to recreate Toki's scar. Amiba then learned enough Hokuto Shin Ken techniques from Jagi to successfully impersonate Toki. With the real Toki imprisoned in Cassandra, Amiba tarnished his image and tortured both civilians and martial artists with his experiments.
He performed "new pressure point tests" on living humans and reported his findings to Raoh. He also claimed that he could learn any martial art under short periods. He develops a style imitating Hokuto Shinken, which he names Hokuda Shin Ken (北蛇鍼拳, Hokuda Shin Ken/"Needle Fist of the North Snake") in Ten no Haō. Kenshiro finally used Zankai Sekihoken, causing Amiba to involuntarily walk over the edge of a high-rise building.
What he did
Unethically experimented upon residents of Village of Miracles including children. Many of them died and those who survived were turned into his minions. By doing this he purposely tarnished reputation of Toki, who was actually healing people there.
Freudian Excuse/Mitigating Factors
None. He had absolutely no care about anyone. He was driven by jealousy towards Toki and he only cared about results of his experiments.
He has a decent bodycount caused by his actions. What makes him stand out from Jagi, Jackal and other villains in the series is that if those mostly resorted to just kill their victims, Amiba tortured and experimented upon them and children were a part of his experiments as well.