The character is described as:
“An enigmatic figure from Jessica’s past, Kilgrave’s reappearance will send shockwaves through the former super hero’s world.”
Tennant joins Krysten Ritter and Mike Colter who will be playing Jessica Jones and Luke Cage.
Kilgrave is most likely Zebediah Killgrave, also known as the Purple Man, a character who has had history with both Jessica Jones and Luke Cage in Marvel comics’ various series. The character has the ability to use mind control using pheromones and also has accelerated healing. The character is most known for his purple skin.