Through an Infernal Contract with Bel you have resistance to fire damage, and you speak and write Infernal.

The Contract:

"You are hereby charged with the execution of Habriel, planetar of Elturel's Companion. If you do not complete this task before Baulder's Gate's fall, your soul is hereby forfeit to Bel who will store it inside a trivial decoration on this mantle with the rest of his collection."