I did some search, and there is a "Shadowheart -- Dark Justiciar card". A "honorary order of secret society within the priesthood of shar"

https://forgottenrealms.fandom.com/wiki/Dark_Justiciars

Rumour has it, they need to kill a cleric of Selune to be eligible...

I wonder if they know each other. Was Shadowheart's kidnapping, despite having the relic, even unwanted pre memory loss? Oh, the drama