Well Shadowheart has the tag 'Evil Cleric' so kinda sure she's not Good at least
Yeah I feel like the only indication to her evilness is the character description (Shar sounds like an evil gal) but nothing in the game itself
Shadowheart is a typical member of Shar clergy:
likes deception to deals with things,
doesn't like fighting heads on or starting fights,
hide her identity,
is secretive.
Shar clerics aren't "Mouahaha, lets kill everyone in gruesome murder" evil. They are subversive evil, they manipulate and corrupt to achieve their goals. Sometimes do assassination, but that's mostly reserved for people who went directly against Shar.
They have to hide and be secretive because the Church is outlawed in most of Faerun.
