His job will be, probably, to give you access to higher levels. If you are of relevant level/XP, the first thing he does, is say something about the next area, which he opens for you. Then he continues his shenanigans.
He could have an entire story to tell you. But for now he's just here to showcase the new, simple, dialogue system.
Mechanically speaking.. you only have to 'talk to' the NPC once, and then you exit the level. You don't have to wait for any dialogue lines. They're cosmetic.
And no, I don't think I want to do the silly trrrrrrr animated text thing.. It can be fun if handled lightly, high speed reveal, subtle sound.. but it's probably very unnecessary here. ^ ^