For the love of order
"Other" rogue's guild cleric
Johann is a cleric of Nerull. The party met him when investigating the split in the other rogue’s guild.
After helping him with some experiments he is doing on preventing healing, he gave the party information about contacting some other members of the second rogue’s guild.
Gilly told him about the death knight armor and it’s ability to prevent healing. She told him that(who was with in the tomb) probably knows where to find the armor.