Starting with 2011’s Thor, the Marvel Cinematic Universe has slowly introduced the Infinity Stones (Gems in the comics). Artifacts of incredible power on their own, when brought together they can give make their owner the most powerful individual in the universe. The six Stones will come together in the near future for the Avengers: Infinity War movies, but as the MCU enters Phase Three, Marvel is rebranding the Infinity Stones so that fans can refer to them by a collective name in the meantime.
As Collider notes, one of the extra featurettes included in the Avengers: Age of Ultron Blu-ray trailer is "Unlock the Infinite Six." Accompanying that was the shot of Thanos from Marvel’s Phase Three slate announcement last year with him wearing the Infinity Gauntlet. There weren’t any other details on this extra given in the trailer, but presumably it will give viewers all the information accumulated on the six Infinity Stones, which are now being branded together as the Infinite Six. Four have been directly introduced in the MCU so far: the Space Stone (a.k.a. The Tesseract), the Reality Stone (a.k.a the Aether), the Power Stone (a.k.a. the Orb), and the Mind Stone (a.k.a. Loki’s scepter).
The Tesseract was introduced in the Thor post-credits scene, and was featured heavily in Captain America: The First Avenger and The Avengers. Loki’s scepter also appeared in The Avengers, though it wasn’t until Avengers: Age of Ultron that audiences learned that the scepter contained an Infinity Stone. The Tesseract is currently locked away in Asgard’s vaults, while the Mind Stone is feeding life into The Vision. The Aether was introduced in Thor: The Dark World, and it was given to Taneleer Tivan, a.k.a The Collector, in the post-credits scene. The Orb appeared in Guardians of the Galaxy, and is currently under the protection of the Nova Corps.
That leaves only two Stones left to be featured (if the comics are any indiction): the Soul Stone and the Time Stone. Marvel hasn’t revealed when we’ll see either of these Stones, although I suspect that 2016’s Doctor Strange may feature a Stone since the protagonist’s magic will likely have some sort of connection to the MCU’s cosmic side. Given that Thor flew back to Asgard at the end of Avengers: Age of Ultron to learn more about the Stones, it’s also possible that Thor: Ragnarok will feature one as well. Either way, we can expect the six Stones to come together when Thanos obtains them and achieves near-ultimate power.
You can check out the Blu-ray trailer below for more information on the film’s extra content.
Avengers: Age of Ultron will be available for digital download on September 8, and can be purchased on Blu-ray and DVD on October 2.