Black Iron Tarkus Covenant

Tarkus aids the player in taking on the Iron Golem as a white phantom. He is notoriously tough and can serve as a distraction during the battle. In fact, Tarkus can defeat the boss all by himself in the first playthrough and stands a break-even chance of doing so on future playthroughs with minimal support from the player.

His Greatsword, Black Iron Greatshield and Black Iron Set are found on his corpse in Anor Londo, next to the entrance to the Painted World of Ariamis. A Painting Guardian stands next to his corpse, possibly removing it from the room since the body is so far away from the entrance.

From the Wiki:

http://darksouls.wikia.com/wiki/Black_Iron_Tarkus