1) Diavolo (Jojo Golden Wind): A schizophrenic Italian man born under mysterious circumstances (his mother was pregnant for two years in an all female prison), he runs Italy's largest mafia organization, harming society with rampant drug trafficking. He wields the incredibly powerful stand King Crimson and seeks nothing more than to erase all traces of his past, including his own daughter that threatens his existence.
2) Nyx (Persona 3): A higher entity and the thirteenth and final arcana representing 'death', with the purpose of bringing 'the fall' or the end of the world and all life on the planet caused due to humanity's very own wishes for the end.
3) Radovid the Stern (Witcher 3): A genius but extremely paranoid and cruel king, he seeks to make Redania all powerful and win the war. His cruelty knows no bounds as he seeks to exterminate all non humans such as mages, dwarves, etc in an extremely sickening manner of tying them to stakes and burning them publicly for the public's entertainment.
4) Mister Negative (Spiderman PS4): Martin Lee, founder and owner of FEAST, a charitable organization for the homeless seems like a charitable person with the best of intentions, but secretly he's the ruthless leader of the Inner Demons, an organization able to harness negative energy at will. He was injected with the 'devil's breath' by Norman Osborn, granting him the terrifying powers he possess, and killed his parents in a rage filled explosion due his lack of control.
5) Wammu (Jojo Battle Tendancies): Cue Ayayayayaya! One of the three Pillar Men (aka Aztec gods of fitness), he lives seeking out worthy opponents and follows the code of honor like a true warrior, never finishing off the weak or defenseless. He serves as the personal rival of Joseph Joestar and only fuels his ambition further after killing his friend Caesar Zepelli (rip Shiiiiiizzaaaaaa).
6) Ushijima Wakatoshi (Haikyuu): The number one volleyball player in the Miyagi prefecture and already a regular for the Japanese national team, Ushijima serves as the primary antagonist that Hinata and Kageyama have to overcome in their quest to bring Karasuno high back to its glory days, having to do so against the formidable Ushijima and his dominant high school team Shiratorizawa.
7) Shaiapouf (Hunter x Hunter): One of the three Chimera Ant Royal Guards, he prides himself as being the most rational of the guards. However, deep down, he only holds a preconceived notion of what a king should behave like, and therefore despises Komugi when he realised that she threatened how Meruem was behaving, less like a king. He goes as far as going against the king just to satisfy his own impression of the perfect king.
8) Cesare Borgia (Assassin's Creed Brotherhood): The illegitimate son of Rodrigo, he too was part of the Templars, and served as the Captain General. However, the order of the Templars was secondary to him, and he even plotted against his father to take over Rome and eventually Italy, with his ultimate desire being the use and exploit of the Apple of Eden.