Underdark: The Endless Stairs, "Roc'aley the Bard" is hostile to everyone (surfacer, underdarker alike), although she does not attack and is immortal. I suspect she/he (not sure) is one of the bard song quest guys for the underdarkers, but is hostile to all.
Also of note, whoever made this NPC dropped the ball and really should have named him "Rick'astley the Bard."