There was a time when Tarnished who had strayed from guidance feared nothing more than utter silence.

You can invade Rileigh the Idle at Altus PlateauGrace. Wields Crepus's Black-Key Crossbow and Scorpion's Stinger, which applies Scarlet Rot. Wears the Confessor Set, this armor is very light and thus he is weak to strong attacks that break poise. Can heal once using a Crimson Flask. Considering the use of the Scorpion's Stinger, as well as the fact that the Black-Key Bolts they use inflict Scarlet Rot, it is possible that Rileigh is related to Maleigh Marais, somehow. If so, it is also possible that Rileigh actually is Crepus, and used the moniker to distance themself from their family's negative history. This would explain why all Black-Key Bolts inflict Scarlet Rot, and not just those used by Rileigh, as Crepus could have created the Black-Key Bolts themself and distributed them to their subordinates. This would also explain why so few Black-Key Bolts are found in the game, as they would all have been made by one person, instead of manufactured on a large scale (which would require sharing knowledge of the poison's heretical secret ingredient, known only by Rileigh).