Blackguard Big Boggart Questline: How to complete Blackguard Big Boggart's Quest
This will also render you unable to purchase Boiled Prawn and Boiled Crab. If you go to the Volcano Manor without speaking to Rya at Liurnia of the Lakes, you will lose access to Blackguard Big Boggart and his questline for the rest of that playthrough.
Never met someone with a taste for prawns I couldn't trust. Blackguard Big Boggart is available as an NPC Summon against Magma Wyrm Makar by progressing his questline. He is involved in the questlines of Rya and the Dung Eater. Initially encountered as the thief of Rya's Necklace, he is a minor NPC and merchant. Blackguard Big Boggart is an NPC in Elden Ring.