>>Falcon was the one that was most against the idea of bringing all the groups together<<

Use "who" instead of "that" for people.

>>They all knew that the Black Hollow had always belong to someone <<

That should say "belonged" above.

>>The black mage who had come from nowhere to take over the Grey Gardens. <<

That's a sentence fragment. If you don't mean it that way, just delete "who" above.

>>He'd never had a hostage before so he wasn't entirely sure what to do with her, but the first thing he was going to do was take her shoes off. That way she wouldn't be able to run away.<<

Unless the outdoors is, say, lava rock or cactus field, barefoot escape is merely uncomfortable, not impossible. *chuckle* But since he doesn't know what he's doing, he probably doesn't know that.