Coming in March 2016, Marvel Battlegrounds will provide a new story as well as new dimensions of gameplay for the Disney Infinity Marvel players:
"In the original storyline, Ultron teams up with Loki in an effort to steal Asgard’s immensely powerful Infinity Stone. To accomplish this, Ultron and Loki create robotic replicas of the famed Marvel Super Heroes and turn them against each other in an effort to distract them while they commit their crime. The Marvel Super Heroes duplicates battle each other in iconic environments such as a wrecked Brooklyn train yard, Wakanda and S.H.I.E.L.D.’s Lunar Base, culminating in a universe-shaking battle against Ultron."Sadly the new 4 player co-op can't mask my disappointment the of the 4 officially known Marvel Infinity characters, 2 of the figures are just costume swaps and not really new. Black suit Spider-Man and Cap are merely new costumes, while Hulkbuster Iron Man and Ultron are at least totally new characters. Although they have yet to officially announce Ant-Man since their teaser months ago.
Source [ Infinity Inquirer ]