Question: dark souls 1 how to join gravelord covenant?
Answer: Have at least one Eye of Death. Three Eyes of Death can be found behind the Prowling Demon in The Catacombs.
Near the same Prowling Demon, there's a coffin which can be interacted with. ... 
Upon arrival in the Tomb of the Giants, look for Gravelord Nito's sarcophagus. ... 
Interact with it to join the covenant.