Just find the waypoint shrine and you can go back to Broken Valey. From the point where you leave Maxos Temple and enter Sentinel Island, keep going ahead to find a guy in a cave. On the left side of the whole rock formation there's a waypoint shrine.
Now those 8 creatures are 8 people. All 8 are trainers (2 necromancers, 2 skill trainers, 2 enchanters and 2 herbalists). You pick 1 between each of those 4 groups, the other one dies. Of course, there may be a way so you don't have to choose yourself...