History
When Kang successfully conquered the whole Mount Avengers (which was the corpse of a Celestial), he used his futuristic technology to destroy the timestream causing all times existing together. In that moment, the Avengers were fighting hordes of dinosaurs or alien conquerors, but at a certain point two of them, Spider-Man and Captain Marvel, disappeared; soon after, they call all the Avengers telling them to be ready for teleportation. The Avengers were been saved by a Thanos coming from the past and so he didn't know anyone of them, Thanos said he want to destroy Kang for having interfered with his plans; the heroes were reluctant, but they eventually decided to accept Thanos' help. The first step included a distraction composed by lots of alien spaceships driven by Thanos' space pirates; they are all destroyed by Kang's energies and Biomechanoids; then a group of Mech Armor created by Tony Stark attacked one of Kang's "trails" that allowed him to use his new powers, but that was another distraction: believing Avengers were into the armors, Kang focused his forces on them, however, the heroes teleported themselves into Kang's base. Thanos was the first one who attacked the time-traveler, but he used his time-based powers and Thanos grew old in a few seconds until oly his skull remains.