Hopefully I'm not misunderstanding you by asking me to put into spoilers which NPC it is, but it's;
Alfira, the Tiefling bard in the Grove who has a very awesome introduction and story.

But yeah, I was not aware of Sven's warning. I really thought Dark Urge is their attempt at making a fully customizable Origin character because in DOS2 non-Origin characters were not as fulfilling in terms of story, but unfortunately lack of roleplaying choices in certain events completely killed the character for me. So gonna save it for a psychotic evil playthrough instead. The character itself is pretty interesting, but definitely not to be mistaken as an Origin Tav.