In Dark Souls, which covenant is led by Darkstalker Kaathe?

In Dark Souls, Darkstalker Kaathe leads the Darkwraiths covenant.

Kaathe is a primordial serpent who can appear in the Abyss after the player defeats the Four Kings. If the player has not already placed the Lordvessel with Frampt, Kaathe offers an alternative account of the world’s history and introduces the Darkwraith covenant. Its members seek humanity and use the Red Eye Orb to invade other players’ worlds.

The covenant is closely connected with the Abyss and with the question of who should inherit the Age of Fire. Kaathe is therefore more than a conventional guide: he represents a competing interpretation of the Age of Dark. Frampt, another primordial serpent, is associated with the opposing path and can appear earlier in Firelink Shrine.