Phaedra

Phaedra is the fourth main colossus. He is found after Gaius and Before Avion.

The main idea is to use the environment. The stones can lead you to a dark tunnel. When he is facing away make your move. Climb up his butt, and onto his back. A mini weakspot will appear, and if hit, Phaedra's head will lower. This can be your chance to attack, and make the final blow.