Who he is: The Collector, a.k.a. Tanaleer Tivan
His power: No superpowers, just an eccentric guy.
His story: The Collector first turns up in a post-credits stinger at the end of Thor: The Dark World, where he’s given control of the Aether, a substance contained in one of the six infinity stones, items of immense power. But his main story takes place in Guardians Of The Galaxy, where it’s revealed he’s made a deal with Gamora to bring him the orb, containing another infinity stone. However, shortly after the Guardians arrive with the stone at the Collector’s residence, Ronan The Accuser shows up (thanks to a drunk dial by Drax The Destroyer, really) and claims the orb for himself, destroying the Collector’s, well… collection of rare stuff. At film’s end, he’s sitting amid the rubble of his collection—a number of whom have escaped, since he was imprisoning them—being licked by a dog and mocked by Howard The Duck.
Played by: Benicio Del Toro
Currently, the Collector is: Licking his wounds and drowning his sorrows, probably. Though it’s possible he’s rebuilt his facilities by now and is back on his feet.
Where will we see him next? Unknown. He’s not listed currently among the characters appearing in Guardians Of The Galaxy Vol. 2, but there’s a chance he could turn up elsewhere in the galactic Marvel universe, such as Thor: Ragnarok or Avengers: Infinity War.