Well, the new trailer for Fire Emblem Warriors: Three Hopes just took our old assumptions and stabbed them.
Seems like Byleth is our foe this time instead of the player-avatar. Beyond that, I did some digging and learned the following:
- That red-eyed white-faced new character at 2:41 is "A mysterious being that appeared in the protagonist's dream. Rescued the protagonist before they were killed by the Ashen Demon and speaks to them as if living in their head. Occasionally acts as if something's missing."
- Shez is "A solitary mercenary. He / she sought to become a famed swordsman, but faced Jeralt’s Mercenaries on a mission and was felled by the Ashen Demon. While training to seek revenge, he / she met the Officer’s Academy students in the woods."
- Nintendo has updated its official overview of Fire Emblem Warriors: Three Hopes with the latest information, part of which is "Align with a leader to build and command an army in 1 vs. 1,000-style battles and deep strategy. The house you choose will bring you through one of three compelling stories, each with a different outcome."
judging from the full cover of the game coupled with what we just
learned, I think Sothis may be a foe this time too, and this does not
look like a Happy Ending story-route like Revelations was for Fates, but
rather a new Warriors version of Three Houses. Not another route, but an
alternate version of the game entirely, with Byleth and Sothis on the enemy side and Shez and red-eyed guy on the good. Regardless, I shall stand with Edelgard in the Scarlet Blaze route just as I did her in Crimson Flower.