Board Thread:Game Discussions/@comment-91.181.37.112-20140909210454/@comment-25097314-20140912130641

It appears to be some combination of level and your gear you have on. I think it's something like +-10/15 levels from your level until you get to level 100ish and then you only fight 100+ once you hit 110 or so but who you fight definitely appears to be effected by the quality of the gear (better gear, fight better opponents).