Thanos

Thanos, also known as the Dark Lord or the Mad-Titan, is a character in Guardians of the Galaxy and the main antagonist of the Marvel Cinematic Universe

Early history
Thanos killed hundreds of people, including the Zehoberei People and several Luphomoids and took their daughters, Gamora and Nebula.

Guardians of the Galaxy
Thanos talks with Ronan, where he threatens to kill the Kree if he fails to bring him the Orb, but promises to keep their bargain if he brings the Infinity Stone to him.

Realizing what is in the orb, Ronan betrays Thanos and takes the stone for himself, but not before threatening to destroy Thanos once he's done with Xandar.

Family
Status: alive
 * Nebula (adoptive daughter)
 * Gamora (adoptive daughter)
 * Numerous adoptive children