Joker

Joker is a psychotic supervillain and a member of the Injustice League.

Personality
The Joker is a dangerous and psychopathic criminal. Although he looks like a clown, he is never to be underestimated. He is cruel, sinister, manipulative and above all completely insane, the Joker has proven multiple times to be the Batman's greatest foe. He also claims to have multiple personalities and has a tendency to break the fourth wall.

Physical appearance
The Joker is a tall, slender man, with chalk white skin, ruby red lips and a head of bright green hair falling down in a mop style. His most distinguishing feature, however, is his massive and wide smile that is constantly on his face, giving him a sinister sort of appearance at all times. He is most commonly seen wearing a purple suit with a flower on his lapel, skinny leg pants, a skinny purple tie and a silver chain at his waist.

Early life
, Joker somehow discovered the location of the Cave and attacked Snapper Carr and the Justice League inside.

2010
Joker had become a member of the Injustice League. They orchestrated a plan involving controlling plants that attacked different parts of the world, adding his own Joker venom spores to some of them. He controlled all the plants in the worldwide assault. Eventually, the Team found the headquarters of the Injustice League in Bayou Bartholomew. After most of his teammates had joined the fight and the plant was destroyed, Joker tried taking down Robin. The Boy Wonder managed to evade his knife long enough for the Justice League to arrive, and Batman quickly disarmed the Joker. Faced with the surrender of his teammates, he released the Joker venom from the plants. Aqualad, as Doctor Fate, sucked the venom away, and Joker surrendered this time.

Equipment

 * Knives: Joker uses jackknives, occasionally two at a time.
 * Joker venom: a chemical Joker created which, when inhaled, causes its victims to laugh uncontrollably until they die with a wide grin on their faces.