I'm really enjoying this game, but I have a big problem.... How do I open the Interloper fortress barrier? Also how do I get a trapped friend out of the savannah??
That particular trapped fella can't be saved unfortunately...
As for the fortress, you need an item from elsewhere. You want to go to the swamplands now, and follow the questline for the serpentfolk. The culmination of that questline will get you a way inside the fortress.