Does Leadership and Kaith stack?

I know Kaith lingers even after you are no longer grouped with the Barbarian that roared. Had a barb grab me in the fens to get a boost to hand the 4 swampies that walked into his room. And was just wonder if we can get a double bonus. i.e. barb leads the group, roars, then the paladin switches to become leader and uses leadership.

They stack.

Neither of them is currently capped, and even so, the cap only affects 1 ability, not both, so if they were both capped, they'd still stack.

Also, the barb doesn't have to be the leader of the group for the kaith roar to work. The paladin can be group leader and LEAD, and the barb could be a follower yet still Kaith the paladin.

And yes, when you combine both, you are VERY powerful in combat. I've done so with a barb and seen the entire swarm cleared in like less than a minute.