There's a character in my group whose concept and high concept are Huntsman of the Erlking (because when our group does things, we don't half ass it) and in the spirit of the Winter and Summer Knight's swords from Our World he has an IoP elephant gun that gives him some Speed and Toughness powers. Problem is me (and the group as a whole, really) is having trouble figuring out a catch for him.I'd suggest using blindness (temporary or not) as the catch. After all, in myth you covered your eyes* to avoid the bad karma / being caught when the hunt rode past. Blindness is both research-able and easy to come by (just cover your eyes) so probably a +2 or even +3 catch - depending on just how often you want to use it in game.
If they are blind however, are they going to be able to fight?
If they are blind however, are they going to be able to fight?Mechanically, I'd run it as a declaration of I'm Covering My Eyes or equivalent. Opponents will almost certainly invoke for effect / compel at which point they can use Stealth or possibly even Athletics to set up a block against targeting. The 'blind' attackers will need to set up declarations (I'm Listening), maneuvers (Flanked), use terrain / zone borders (move into the hall), and possibly invoke a few of their own aspects to break through the block and hit.