I know it would be hokey / cliche but I think it would be neat to see if you could find "US" among the 3 living intellect devours that are roaming around when you wake up on the beach. It might be a fun thing / skill check to see if he 1) still recognizes you as a friend and if so helps / becomes a follower ( help all those classes who cant summon familiars to scout and could nerf his ability just to do that) / camp follower or 2) help in combat against the other ones and or the wounded mind flayer ( visions of " Don't hurt friend"). I would also make it random among the 3 so you would have to try interacting with all of them, not just snipe them off from a distance and hope you find the correct one.
He could also be used as a barometer of how far the tadpole has progressed. What I mean by it is he gets more and more receptive to you as the tadpole gets a stronger hold on you. When you get rid of the tadpole, he gets sad / withdrawn and leaves the camp and you. " Friend no more"...
Just a thought
