Can I get a hint for finding the mechanic?

[Skull]

I really want to help Karlach, but genuinely have no idea where I should look. I don't want to just search online because I'm not looking to have the answer fed straight to me, but this game is not giving me anything to work on, other than "tiefling." And now Karlach said she doesn't think she has much time left, and I don't know how much longer she'll last and I don't want her to die.
I would appreciate just a small nudge in the right direction, that'd help a lot.

[arikel.pv]

Explore the territory to the north of the Nautiloid crash region. You'll find even more than one horns-tails wielder there
Don't worry for the time left, you have at least the half of Act I to start helping Karlach

[JayPAC]

This game suffers from a sense of false urgency. You have all the time you might need to run into the mechanic. Since you have Karlach with you... you might have already met him. To stay cleer of spoilers, I'll just say that the post before mine tells you all you will need.

[Requin]

You can find him at least once in all three Acts, and he'll be gone in Act 1 if you go and do the celebration for wiping out the goblins. But don't worry about running out of time, I was rattled too, but you have time.
Have fun with the best girl, brother