After doing an excellent job playing Albert Wesker in Netflix's canceled Resident Evil live-action adaptation, it appears that Lance Reddick is now coming back to reprise his role as Sylens from the Horizon franchise.
Reddick himself confirmed his return as Sylens, in what many presume is DLC content for Horizon Forbidden West, after he uploaded a video during an ongoing session. Reddick has since deleted the video but someone on Reddit got a copy for everyone else to see. This move implies that Reddick didn't intend to leak the upcoming expansion or DLC content for Horizon Forbidden West.
Reddick's character, Sylens, plays a key role in the Horizon franchise. He is Aloy's mysterious ally and mentor. The second game shed more light into Sylens' checkered past and how he's manipulated his way to achieve his goals. However, by the end of the sequel, Sylens appears to have had a change of heart. He's now on Earth to help Aloy against Nemesis.
Considering that Forbidden West ended with a cliffhanger, it makes sense to release a form of post-launch content if only to tide audiences over until the release of an inevitable third game.