King of Despair

The King Of Despair (絶望王, Zetsubō-ō), is one of the Thirteen Kings and the main antagonist in the anime's first season. Since the Great Collapse, he shared a body with Black.

Appearance
The King Of Despair's original appearance was unknown but was chronologically first shown as a mysterious figure cloaked in flame. Due to possessing a human, he wears the same clothes as said human but under a long blue overcoat and has messy, blond pushed back hair. His eyes are the same color as blood from a freshly cut wound.

Personality
The King Of Despair is laid back, cunning, and has little respect for others. He has an affinity for twisting peoples emotions against themselves, which he shows no remorse to.

Plot
He first appears at the end of Episode 1 spying on Leonardo Watch at a crushed Dianne's Diner. Several days later, in Episode 4, he approaches Leo again on the subway, talking with him about the population within Hellsalem's Lot while also warning him about the Blood Breed. He seems to be acquainted with The King of Depravity.

At the end of Episode 7, The King Of Despair is seen donning a blue overcoat as he walks into Femt's hall, shouting at the other ghouls that it's now his turn. He mentions that it's his turn to bring about the Great Collapse, as he's found "it".

During Episode 9, he meets up with Femt and Aligula, commenting on how they are both easily entertained. Later on, Aligula provides The King of Despair with a device to use of Leonardo's eyes, which makes him overjoyed, stating that he thought they were impossible to get.

The King Of Despair was present during the first Great Collapse, appearing as a mysterious being cloaked in flame. William and Mary are seen in front of him and William refuses to let him take over his sister. Instead he offers his body to save and protect his sister from being possessed, thus accepting The King of Despair.

The King of Despair manipulates White into getting The All-Seeing-Eyes of the Gods, telling her that he'll let White have her brother back if she gets Leonardo's eyes in exchange.

After having White lure Leonardo to the church, she places the device over his eyes in hopes that she will get her brother back. The King Of Despair is seen dragging Leonardo down into the other world after being knocked out by the device on his eyes. He uses the device on Leonardo's eyes to destroy a seal, setting off explosions in Hellsalem's Lot in the process.

At the end of the episode, inside the same church, he is seen sitting next to an unconscious White, while talking to himself. Despair contemplates about the "lingering affection", most likely referring to the barrier White's parents used to replace her heart (thus keeping her alive as a barrier). It is implied the same affection was what led Black to accept the King of Despair into his body. The King lays White on the bench, presses a gun into her chest and shoots while saying that he truly loved her. However it is not shown that Mary took the bullet to the chest and died.

In Episode 12, The King Of Despair is seen waking up after killing White. He is visited by Femt, and King of Despair is told that Leo should be on his way, to which he replies bitterly "You let him go." Femt then goes to speak about the King Of Despair's past, stating He's gone by many names in the past while forced to simply watch as history repeated itself over and over. As Hellsalem's Lot begins tearing itself up, The King Of Despair is seen sitting at the alter of the church whistling as he waits for someone. Klaus Von Reinherz appears before him and asks what will happen to Black after this is all done. He says that he hasn't given up on Black, and when Klaus holds him up by his neck, The King Of Despair is seen telling Klaus mockingly to save him from himself.

When Leo appears midst of their fight, The King Of Despair denies the claims that they all had over him, telling both Leo and Klaus that William had willingly accepted him but is interrupted by Leo, who says even if that's true he can still see Black. Through Leo's broken vision, he can see Black standing behind King Of Despair crying while saying he doesn't want to die, but wants to live. When Leo forces his eyesight upon King of Despair, he pushes Leo away angrily while telling Black to go back to sleep. As a ghostly version of White walks towards him, Black's body soon gives out and he passes out. When Black wakes up, White is laying her head on his chest and he asks her what she's doing, to which she replies she was simply checking if he was still alive or not. White offers herself to be used as a sacrifice in order to complete the seal, and Black begins crying saying he cannot live without her as a life without her is no life at all.

When she convinces him of what they must do, he agrees with tears in his eyes. White effectively banishes King Of Despair from Black, but also becomes a part of the seal that protects the city. Black is shown watching Leo cry from a distance, talking to White as if she were still there. He calls Leo their hero, commenting on how he looked brave even while crying.

In the credit scene, there was a man walking through the street, whistling the same melody as The King Of Despair once did when he inhabited Black's body, hinting that the members of Libra haven't seen the last of him.