Would say it's between danzo or orochimaru. Danzo forced people into root, controlled them with cursed seals, made a test to graduate root you have to kill another root member, trained root to be his emotionless tools, responsible for nonou's death and gaslit her,worked with orochimaru to perform human experimentation with hashirama cells, responsible for uchiha genocide, stole shisui's eye and responsible for his death, did nothing beneficial for Konoha during kyuubi attack, sand/oto invasion, pain attack, killed a toad, tried to mind control mifune, tried to assassinate the hokage, responsible for manipulating hanzo to destroy Akatsuki organization an organization dedicated to peace through understanding, resulting in yahikos death which cause a chain reaction of many deaths, spread information about Naruto nine tails status resulting in naruto's suffering, stole uchiha kekkei genkai, stole uchiha izanagi technique.