Not much is known of Thanos, except that he is known as the evil Mad Titan and destroyed his home planet.
Thanos also slaughtered Gamora's entire race, and adopted and brainwashed her as his personal assassin. His other adoptive children were Nebula and Korath. At some point, he recruited Ronan The Accuser, an exile of the Kree Empire, as his top general and allegedly ordered Ronan to commit a murder that included Drax's family. Later on, Gamora defected from him and Ronan and Nebula betrayed him. Thanos also came in contact with Emperor J'Son of Spartax, Peter Quill's father. In Guardians of The Galaxy, which seemingly takes place before Avengers Assemble, the Guardians have to keep him from getting the Cosmic Seed. Thanos sent out his Lieutenant, Korath the Pursuer, to get the star-map that will lead him to the seed. Drax also seeks revenge against Thanos for killing his family. Thanos also came in contact with emperor J'Son of Spartax, and agreed to destroy Asgard if J'Son gave him the Cosmic Seed. When J'Son was exposed, he called Thanos and his army to Spartax, leading Thanos to kidnap Star-Lord and attempt to force the location of the Cosmic Seed from him. Star-Lord tricked Thanos into destroying the Cosmic Cube and threw him into a black hole. Thanos ended up surviving, and arrived on Earth, punished Ronan for his previous betrayal, and stole the Cosmic Seed to turn the Earth into his personal superweapon to destroy entire worlds. The Guardians last fought him in New York City and succeeded in stealing the Cosmic Seed back from him, leaving him to be rammed by a subway underground.
By Avengers Assemble, Thanos survived his last battle with the Guardians and had the Red Skull bow down to him. Eventually Red Skull betrayed Thanos and escaped back to Earth while Thanos chased him only for Thanos's ship to be destroyed. Eventually Thanos found the Avengers and the Power Stone, but the stone blew up. Thanos survived the explosion, but was taken halfway across the universe and went to get the other infinity stones.
PERSONALITY AND TRAITS
Thanos is an utter megalomaniac of pure evil, the only thing he respects is power and craved nothing more than the subjugation of the entire universe. Besides a narcissistic need to be invincible Thanos is one of the most feared beings in the galaxy, Red Skull was in obvious terror in his presence and even at a different planet his cruelty was known and reviled, he can at times be somewhat merciful such was shown when he was captured by the Avengers during his pursuit for the Power Stone and bargained he would spare the Earth if they handed over the Red Skull and the Stone but in spite of this fact, he is also an utterly psychotic, vicious, ruthless, arrogant, and sadistic tyrant by nature. In his quest for power Thanos nearly killed all of his race, was perfectly happy destroying the Earth to prove the Infinity Stone's might and almost destroyed a populated planet to get even more power.
After finally collecting the entire Infinity Stones, Thanos became even more cruel, aggressive, and egotistical. He came close to destroying the entire Earth by changing it's climate but then engaged in a duel with the Avengers by them damaging his ego. Finally the Mad Titan was defeated and delivered to the Guardians of the Galaxy for his crimes against the universe.
- Unlike his comic counterpart, he has no love for Death.
- Thanos' soul is currently spread out across the universe, but it is implied by Iron Man that he will be able to pull himself back together in a matter of 100 years.
- Unlike his Comic Book and MCU Counterpart, this Thanos is a Complete Monster.