Paint it Black is the 11th episode of the Kekkai Sensen anime.
As the origins of White and her brother are revealed, the King of Despair uses the power of Leo's eyes to ignite a huge catastrophe on Hellsalem's Lot during Halloween.
White recalls her younger days with her father Benjamin Macbeth and mother Emma Macbeth. Even though she comes from a family tree of casters, White has no psychic powers, while her twin brother Black seems to be powerful for both of them. He unconsciously sometimes releases his power when he cries, but had decided to not use it and often gets beaten by other boys. Benjamin explains that its not necessary for them to be casters and wonders if White had forgotten why Black ended up not wanting to be a caster and it was a big deal, but as Black shows up, she stops her father from saying why. White ends up having interest in taking pictures, but one day boys take her camera. Black tells them to return it, but as they throw it of a bridge, he jumps in the river to catch it. Since he almost drowned, he was in hospital and White explains that she didn't care about the camera and that he should use his powers and shouldn't die.
Later Black tells her about a time when she made a perfect mud ball, but he being jealous, he broke with it his powers. White immediately went to make a new one without saying anything and he felt left behind, so he decided to become strong on his own and not users powers until then. White comments that their father said it was some big deal when that happened and Black explains its because he cried a lot after that, which made both Black and White to start laugh. Black tells her that she is good at photography and he also tried to take a picture of her while she sleeps, but ended up quite blurry. Seeing the picture, White starts crying, hugs him and thanks him. White later encourages Black to become a caster and to start practicing.
At the chapel, White apologizes to Leonardo and the King of Despair uses Black's psychic powers to hold Leonardo. White explains that he needs to get Black back from him and for that Leonardo is essential. She places the device over his eyes and Leonardo collapses.
The King of Despair takes Leonardo to different place, where he uses a magic circle and Leonardo's powers. After that he tells Leonardo that White isn't human and that she is only alive because her parents made a barrier in place of her heart. Later at the chapel, King of Despair shoots White in the heart. Elsewhere Femt observes the destruction the King of Despair created and comments the Second Collapse begins.