Mephiles

Mephiles is an Etherious created by Zeref, the true guild master of Black Void, and a former member of the Tartarus guild. Due to his Body Controlling Curse, he is currently hosted by Jason Gaebolg.

Appearance
Mephiles appears as a completely black humanoid with no facial or other notable features. His body appears fluidic taking the form of a black, tangible mist.

Personality
Mephiles is evil and sadistic, willing to do whatever it takes for him to rise to power, originally hoping to use Jason Gaebolg's body to take over the Tartarus guild. However he is willing to lower himself in order to achieve his goals, such as allowing Jason to keep control of his body and even giving Jason power in order to increase his power.

He is also very manipulative, tricking Jason into creating the Black Void guild and the Magic Council, through Jason, to allow several Dark Mages to be released from prison in order to join the guild, as he wanted this guild founded can for his own motives.

History
Mephiles was created approximately 400 years ago by Zeref for the soul purpose of killing his creator. Although he found that most difficult to do among his kin, as he was not even able to control Zeref's body with his curse. Mephiles spent the rest of his life searching for a suitable vessel to use to kill his master. He was also present when E.N.D founded Tartarus. He later participated along with theretst of Tartarus in the battle against the Doomkaisers and was present when Mard Geer killed their leader.

Mephiles ran into Jason Gaebolg 400 years later, hoping to be able to use his body to kill Zeref, however Jason managed to hold Mephiles in his subconscious through sheer willpower. Mephiles was able to gain control of Jason's body for split seconds at a time forcing him to kill innocent civilians on several of his missions. Realizing he'd never gain complete control over Jason's body he submitted to him and allowed him to use his Demon Eyes Magic. Mephiles and Jason then left the Tartarus Guild on their quest to kill Zeref. The two then managed to convince the Magic Council to allow them to found the Black Void guild, consisting of mostly former Dark Mages.

New S-Class Mage Arc
Mephiles was first introduced alongside Jason. He led him to a dark guild hall and egged him on to slaughter the entire guild with Amaterasu.

He later questioned Jason on why he threatened their employer on their way back to the guild with Jason asking why he cared. He also assisted Jason in getting rid of Hayley Barker by threatening to kill her if she asked about the results of the S-Class Promotional Trial.

After the results for the S-Class promotional trial were revealed Mephiles noted the angered faces on Hayley, Cane, and Thomas and warned him that they intended to kill him, to which Jason replied "they couldn't even if they tried."

When the three candidates confronted Jason on picking Victor Cras for the next S-Class Mage He quickky read the situation and could tell this was their attempt at his life. He then berated Jason on not fighting back when he was being beaten by the trio. When Jason talked to Mephiles after the fight he mentioned that this would be a small bump on their journey to kil Zeref.

The Boy With the Demon Eyes Arc
Mephiles questioned Jason on why he offered Alexander Doomkaiser membership to the Black Void guild, to which Jason replied he made him feel fear. After Mephiles stated that Etherious didn't feel fear, Jason rebutted this by saying everything felt fear.

Mephiles later commented on the power of the Lunar Eclipse Eyes, but noted their uneffectiveness on Etherious and how Mard Geer killed their leader in the past. He also showed surprise at Jason deciding to take on Alexander as an apprentice.

Mephiles later instructed Jason on what to say to Alex during their mission to recruit Luke Gandor, and was angered upon Jason saying something he hadn't instructed him to. After one week of waiting for Luke to show up, Mephiles noted how often Alex complained.

Curses and Abilities
Body Controlling Curse: Mephiles is capable of using this ability to take over the body's of his opponents. However powerful enough opponents can resist his influence. He can also willingly give his power to his host, allowing them to use his curse, or increase their overall power.

Trivia
His name was based off of Mephiles from Sonic.