From Destinypedia, the Destiny wiki

Just saying, (don't dislike me or whatever) but I think Kells who are never seen in the game but are mentioned in a Grimoire intry, should be named Kell of (House Name), (example: Craask, Kell of Kings or Kell of Scar.), while Kell in the game, should be named (Fallen Name, House Kell), like as for an example: Draksis, Winter Kell.