tinfoil hat time, since there's only three more days 'till Call of the Mountain is released and theorizing becomes moot.
Also, i just can't let go that there keeps being mention of Ryas's face and/ or identity is important in relation to the Carja's lore and history.
**As always, spoiler discussion for Horizon Forbidden West**
I know it's primarily VR marketing with playing first person yadayada that you don't see the protag's face but consider: the narrative impact of a face/ identity reveal.
Ryas would need to keep his face covered to conceal his identity for multiple reasons, the least of which are:
clearly identifiable upperclass Carja family marks
notorious reputation as established from the Red Raids and known reputation as a member of the Shadow Carja
tribal grudges against the Carja at large due to the Red Raids
If nothing else but to have direct character and narrative parallels to, Nil is another character who keeps his identity concealed:
clearly identifiable family marks as an upper social class Carja (Ligan of the Hunter's Lodge has the same markings as Nil, so reasonably noble class, especially given the history of the Lodge's membership requirements)
notorious reputation established from martial renown in the Red Raids (conversation overheard from guards during the Looming Shadow main quest about Battle of the Daunt and Cinnabar Sands skirmish)
tribal grudges against the Carja at large due to the Red Raids (as said explicitly by Nil, of specifically the Tenakth holding vicious grudges from the time of the RR, but also seen in the animosity held by the Nora and Oseram, and reticence of the Banuk towards the Carja)
It is of great emotional importance to reveal Red Teeth as Nil as a marker of progress and growth in his personal character arc. It's a definitive sign of vulnerability and trust to a person he clearly regards closely and equally.
The emotional significance of reclaiming identity is very important to those who are or were disgraced by their actions or in regard to their honour code. We've seen it in Nil, maybe we'll see it with Ryas; and hopefully, a connection between the two.