I don't think you actually need to talk to brutus first, iirc, my first play through I went to high hall before going to the harbor, you need to kill one troll that drops these rune orb things, that lets you in through the barrier in the cave.

btw, there are 2 entrances to mundus' cave, if you go in top entrance that rune troll is up on that level.

Last edited by Jingizu; 01/06/10 12:28 AM.
My mind works like lightning! One brilliant flash, then it's gone. >.>