Guardians of the Galaxy
The characters shown in this picture above are the GOTG members based on the 2008 line up and the same 5 characters appearing in the film premiering in theaters next year on August 1st, 2014.
Now for the villains the Guardians will be teaming up with S[ider-Man and Nova against:
As shown from this picture above the villain in the middle is speculated to be The Collector as the gray alien soldiers around him are speculated to be the Chitauri from the Avengers movie which could mean that Marvel has approved their permission to appear in animated shows like other MCU versions of the characters from the past movies but we will see soon enough.
This episode is also to feature Groot voiced by the late Michael Clarke Duncan which considers the character as the late actors last role in animation voice over which is one good reason why everyone must watch this episode as well. So tune in for Ultimate Spider-Man on Sunday July 21st on Disney XD.