Does a feral hunter have an "official" deity? Or can I select one that I find suitable? Because in that case every character could take the feat. Otherwise it is only for clerics/druids/paladins etc...
Yes. Every character may venerate 1 deity or philosophy. That's the one that applies to feats and traits and spells. The character can honor other gods or a pantheon of gods as well, but they don't count for feats etc.
RainyDayNinja
RPG Superstar Season 9 Top 32, RPG Superstar 2014 Top 16, RPG Superstar 2013 Top 16
An oil of bless weapon is a cheap solution, better than spending a whole feat.