Karlach was a citizen of the Lower City of Baldur's Gate before being taken prisoner and forced to fight in the Blood War, the eternal conflict between demons and devils. She was a prisoner and champion of Zariel, Archdevil and ruler of Avernus.

Karlach was locked away in the dungeons of Avernus, due to her betraying Zariel.

Karlach see’s you, walking through an..inter dimensional portal??

”What the—? What am I…witnessing..? A—A portal?”

Karlach exclaims to herself!