The Batman Who Laughs

The Batman Who Laughs, also known as The Darkest Knight is a evil version of Bruce Wayne and one of the main antagonists in the DC Franchise. He serves as the secondary antagonist of Dark Nights: Metal, one of the two main antagonists of Dark Nights: Death Metal (alongside Perpetua), the titular main antagonist of The Batman Who Laughs seven-issue miniseries and one of the two main antagonists alongside Lex Luthor in the Year of the Villain saga.

He was once a heroic Batman of Earth -22 who got exposed to a strong toxin he inhaled from the dying pivotal antagonist Joker of his own Earth. During the events of Dark Nights: Death Metal, he has gained the powers of an another Batman counterpart with the powers of Doctor Manhattan, he eventually turns into a being of pure darkness known as the Darkest Knight.

He plays as a protagonist in his debuted appearance in the graphic novel comic The Batman Who Laughs #1, the titular antagonist of the seven-issue miniseries of the same name, the secondary antagonist of Dark Nights: Metal, and one of the main antagonist of Dark Nights: Death Metal.

What made him heroic?

 * He server as Gotham's vigilante to fight against crime in the honor of his parents.
 * He had tried to stop the Joker and somewhat succeeded in stopping him.

What made him villainous

 * Although he starts out as a hero he sheds off many of his heroical qualities once he is jokerfied becoming briefly brainwashed and have cosmic intelligence and chooses to become the Darkest Knight.
 * He assists Barbatos in his plans to plunge the entire Multiverse into darkness.
 * He attempts to murder the Justice League (all failed).
 * He ends life on on Earth -22, his universe (succeeded).
 * He had tried to end all life in existence and infect Gotham City and the rest of Earth with Dark Matter.
 * He had tried to destroy the multiverse and recreate it in his own twisted image.
 * In spite of the heroical qualities he had earlier on. Most of his heroical aspects he once had are shed away as he rejected the chance of being helped and redeemed by his remaining closer allies killing them. And he has taken pride into villainy choosing the dark path instead of any chance of being able to redeem himself choosing to be a hero instead.

Trivia

 * He is one of the most scariest interpretations of The Dark Knight to be not only in the path as a villain let alone be a Fallen Hero showing what the mainstream Batman could have possibly became, but Pure Evil as well.