About 2/3rds of the way through, you will get to the "Ruins of Rekem".
Your character should be quite a hard dude by now, and after the cut scene, you get a Titan and some skeletons. Activate stone armour and just power attack his legs (hold X), until he kneels down. Then jump up on him (A) triggering a cutscene, and hit X when the Prince's sword flashes white light.
After this, just let the skeletons kill you, don't rewind time, and the checkpoint start is where the Titan spawns. As a result, if you want to, you can knock this out in 5 minutes.