Mephistopheles
Mephistopheles is a villain and the well-known "King of Hell." He has a blue/green skin tone and his facial formation and horns resemble a ram's head. He carries a massive trident as his weapon. The evil ruler of hell, Mephistopheles enjoys enslaving souls and corrupting people. He enslaves Xena's mother, Cyrene, to make a bargain with Xena. His desire is to obtain the blood of Eve, Xena's daughter and a messenger of Eli, which will allow him to ascend upon the Earth and be made flesh. When made flesh, he hopes to conquer the mortal plane along with hell, joining the two together and leaving the gateway to hell forever opened. With no "devil" to rule over hell, the gateway would forever remain open and demons would swarm the Earth, turning inhabitants into dark servants of hell, in turn making them undergo the "heart of darkness". This phase would consume the people with hate and take over their emotions. Xena, Gabrielle, and Eve return to Amphipolis to discover that Mephistopheles has slain Cyrene and is willing to do anything to become flesh. Mephistopheles possesses Gabrielle's body and tries to transmit the message that he needs Eve's blood or else he will continue to torture Cyrene's soul. Xena allows Gabrielle to perform the pinch on her so she can travel into hell temporarily and battle Mephistopheles. Once there, she witnesses the suffering that her mother is being put through and she faces off against Mephistopheles. However, as Mephistopheles blatantly tells Xena, she cannot defeat him in the realm of hell. Therefore, her god-killing powers are cancelled out in this battle. Also, he tells her that if she were to kill him, she'd have to take his throne as his successor. Xena is not able to overcome Mephistopheles but she promises that if he were to come upon the Earth, she could kill him. Mephistopheles accepts the challenge. When Xena returns to the Earth realm, Mephistopheles is already using his demonic illusions to haunt Eve so she will spill her blood in his name. Eve succumbs to his desire, and the gateway to hell is opened, allowing Mephistopheles to ascend upon the Earth. Mephistopheles is overjoyed to have finally been made flesh, but his victory is short-lived as Xena continues to do battle with him now on Earth. Xena does not particularly want to kill Mephistopheles because she does not want to replace him as the king of hell. But when Mephistopheles threatens to continue his madness, Xena calmly mutters "So be it," before slicing his stomach with her sword, killing him. Afterwards, Lucifer the archangel is sent down to force Xena to accept her position as the ruler of hell, but she tricks him into committing the seven deadly sins so that he becomes the successor instead.
Read more about this topic: List Of Xena: Warrior Princess Characters