Breath of the Wild 2 is the placeholder title for a sequel to The Legend of Zelda: Breath of the Wild, but there is a chance it will feature a different Link from the one who appeared in that game. Instead, it might headline the version of Link that appeared in Hyrule Warriors: Age of Calamity, which created an alternate timeline with its ending. Should this be the case, it could explain some of the changes to Link shown in the trailers for BOTW 2.
Trailers show Link using new equipment and powers in BOTW 2, including a brand-new arm. One scene shows Link defending himself with a blast from a flamethrower, and another has him use the aforementioned arm to seemingly reverse the trajectory of an object rolling at him. While Breath of the Wild also featured a variety of different weapons for Link to utilize, this new arsenal could be necessary for BOTW 2 should the main character be Link from Age of Calamity.
Link's new arm in BOTW 2 could end up being a replacement for the Sheikah Slate. Link utilizes the ancient device throughout BOTW, but in Age of Calamity, Zelda is the primary holder of the Slate. As explained by Robbie and Impa, the game's other characters can only use the Slate's runes due to the presence of mini-Guardian Terrako strengthening it. However, the trailer for BOTW 2 hints Zelda and Link may be separated, showing Zelda falling into a chasm. In this case, the Age of Calamity Link would be left with no Sheikah Slate to guide him, perhaps explaining the necessity for the new arm's features.
Zelda: BOTW 2 Could Explore Hyrule's Distant Past Using Age of Calamity's Link
Unlike Breath of the Wild's Link, Age of Calamity's Link has the potential to travel through time in the events of BOTW 2. Trailers for the game depict two very different environments: Some scenes show Link in his familiar Champion's Tunic in what looks like classic Hyrule, while other shots feature a wild-haired Link in an antiquated outfit traversing new, floating landmasses. This alternate landscape could possibly be the ancient Hyrule of 10,000 years prior mentioned by Impa in BOTW.
With Age of Calamity's secret ending restoring Terrako, the Link from that timeline could possibly travel back to this older time period to find out about the mysterious figure and arm, then back again to his era to search for Zelda. In this way, two similar (yet different) versions of Hyrule could be experienced in one game, similar to The Legend of Zelda: Ocarina of Time. Since Terrako is not present in the first BOTW, that version of Link would not be able to use this same method of time travel, making this specific scenario really only possible in Age of Calamity's timeline.
The timeline and version of Link that will feature in Breath of the Wild 2 is still purely speculation at this point. However, it seems plausible that the game could be just as much of a sequel to Age of Calamity as it could be to Breath of the Wild. Doing so could clearly establish Age of Calamity's place in the series and allow for further expansions of its branched timeline in the future.