Two Giants

The Two Giants Easter Egg is perhaps the toughest Easter Egg in the entire game. Found only when the player loads the level Osiris, on Legendary difficulty. In order to find it, the player must find and ignite seven knives found throughout the level. There is a rocky ledge on the top-right when the player first starts the level. An important note is if the player melees the knife, the other six won't spawn, perhaps due to a glitch. The second knife can be found near a downed Banshee, after the first Soldiers are killed. A weapon with a scope is required. The third knife is found on another rocky cliff that can't be accessed by players. the fourth is found in a small, dark area above some wreckage of a Banshee. The exact location is unknown, so grenades have the best chance of igniting the knife.The next two knives are unknown, but the final knife is found on a platform that is in the final room, of which players exit to end the level.

Once the blade is ignited, a giant Knight and Warden Eternal will spawn. The Knight will charge as soon it spawns, while Warden will stay put until he is damaged enough.

The Legendary rated Prophet's Bane and Plasma Pistol will spawn as well.

What's interesting to note is while the Knight is equipped with a Scatter Shot, it won't be dropped as a usable weapon when the Knight is killed. The Knight also can't be stunned, only pushed around.