Are you Light Side or Dark Side?
Light side is very easy. With the regnerating power-ups inside the Tower, you have infinite health and force absorbtion, so all you need os patience.
If you are Dark Side, it is damn difficult. Jerec is immune to jsut about everything you can throw at him, and your health will wear down. But you get a MUCH better end sequence!
Once you wound Jerec enough, he runs to the central tower to heal. While he is doing this, the staues move around outside- flick the switches to stop them.If the statues ever move all the way, Jerec has unlocvked the secretlf the Valley and won.
The trick is to kill him when he is wounded, BEFORE he makes it to the tower to heal. This can only be done with patience; try to get him stuck against some scenery or something.
Every blow you deal to him while he is fleeing will properly wound him. Repeat the process a few times, and he should die.
But pateince is to the fore here.
As an ultimate battle, ist was fair enough in the power stakes, but gameplay wise this duel is very dull...