The World Government was created nearly 800 years ago after a massive war engulfed the world of One Piece. This government was formed by 20 Kings joining their forces and, since then, their influence on the world has only expanded even more.
Currently, over 170 countries are allied with the World Government. While on the surface, the World Government looks like an organization that maintains peace and protects people, the truth is anything but that. There are countless evil people that riddle the forces of the World Government and do more harm than good.
7 Sakazuki
Sakazuki is the current Fleet Admiral of the Navy in One Piece. Before the time skip, he served as one of the Three Admirals and made quite a name for himself during that time of his life.
Sakazuki believes in Absolute Justice. This means that he eliminates anything that he feels goes against his justice. In following his own brand of justice, he has killed countless innocents and even murdered children. Undoubtedly, he's one of the most evil characters in One Piece.
6 Spandam
Spandam is a character that One Piece fans are very well familiar with, given that he's one of the most hated people in the entire world of One Piece. He was the leader of CP9 and, even though he best no combat-related abilities, he was quite high up the pecking order.
Spandam caused a great amount of misery to the survivor of Ohara, that is, Robin. He also did whatever he could to please the Five Elders to gain even more success in his own life. He is one of the most hated characters among the fans and he has earned that position for himself rightfully.
5 Cipher Pol Members
The Cipher Pol members are the lap dogs of the Celestial Dragons in the world of One Piece. While there are many Cipher Pol organizations, running from one to nine, only two are prominent in the story and that is CP9 and CP0. The CP9 were the main antagonist of the Water Seven Saga while the CP0 are more prevalent after the timeskip of the story, and are a secret organization.
Regardless, both organizations are evil to the core. The CP9 did the dirty work of the Government for them while the CP0 are the direct underlings of the Celestial Dragons and aid them in whatever dirty work they require to be done. People who serve them are certainly evil to their very core and hated for the right reasons.
4 Roswald
Roswald is one of the Celestial Dragons that the fans of One Piece are very well familiar with. He made his debut during the Sabaody Archipelago arc, where he was seen at the auction house with his family. Roswald caused a great deal of problems for not just Camie but also the Straw Hat Pirates.
Being a Celestial Dragon, he is rotten to the very core. He holds countless slaves and treats human life as if it were nothing. Roswald doesn't even want to breathe the same air as a regular humans, which makes him a despicable character.
3 Charloss
Charloss is the son of Roswald and, somehow, an even worse character. Just like his father, he believes in all the evil practices of the Celestial Dragons and he takes them a step further.
He has killed several of his very own slaves and kidnapped other people who he wanted to become his plaything. He even caused trouble for Camie and, later on, during the Reverie, for Shirahoshi. Charloss is certainly one of the most evil characters in One Piece and, for that, he has been on the receiving end of quite a few beatings already.
2 Gorosei
The Gorosei are incredibly powerful characters in the world of One Piece. To the common people, they are the highest authority in the World Government and the highest ranking of all the Celestial Dragons that live in the Holy Land of Marijoa.
Every major decision that is taken by the World Government is either passed by them or through them. As such, they are complicit in every single evil activity that goes on in the world of One Piece, such as slavery, human trafficking, and war, among other things.
1 Imu
Imu is the sovereign of the entire world and their identity has been hidden from everyone in One Piece. They are immortal and have been alive since the time of the Void Century. Imu is the person who played a role in the destruction of the Ancient Kingdom and, eventually, seized all the power of the world for themselves.
They have committed mass genocide on multiple occasions, as has been hinted in the story already, and if that wasn't enough, they have played an active role in every single evil act committed by the Government. Surely, Imu is one of the most evil characters in One Piece.