Batman Who Laughs

In the dark Multiverse, The Batman Who Laughs is a major villain in DC Comics who is the commander of the Dark Knights that seek to plunge the Multiverse into darkness, making him and his team foes to the Justice League.

What makes him Pure Evil
Brutally murdered his allies, the Justice League.

Completely exterminated everyone in his world except for himself, Alfred and his Jokerized Robins.

Tricked Alfred into thinking he still had some good in him and then trapped him in his Batcave for a year before Alfred finally snapped became his loyal servant.

Remorselessly attempted to annihilate the Multiverse as ordered by Barbatos.

Released inmates out of the Asylum, many of which had homicidal tendencies that made them very dangerous to the people around them, in some cases including themselves.

Tried to destroy the earth after Barbotos and the Dark Knights were defeated.

Infected Shazam, turning him into The Shazam Who Laughs.

Surpasses even the Joker, a psychotic mass murderer himself, in terms of heinousness as the Joker is shown absolutely loathe him (The Batman who Laughs), teaming up with Batman twice to stop him and becoming deathly serious whenever referring to him, such as calling him "a wrong thing that should not exist."

Destroyed all his redeeming qualities.