Blurg can be first met in the Ebonlake Grotto at X: 111 Y: -89. If telling him about the tadpole, he contacts Omeluum and the pair attempt to learn more information about it. He also shares details about the Society of Brilliance along with his scholarly insights on the Myconid colony and the Underdark.
Otherwise, the two have traveled together to tell the Society of Brilliance about their findings. If spoken to after both travelled together, Blurg worries that Omeluum has been gone for too long, and asks the party to find it; this starts the quest Retrieve Omeluum.
Blurg appears briefly in the Fifth Edition Dungeons & Dragons Module "Out of the Abyss." While still a member of the Society of Brilliance, he was originally an Orog, an uncommon subrace of Orc, rather than a Hobgoblin. Some of the dialogue related to him even reflects his original race - implying the hobgoblin model was originally a placeholder, but was eventually used for the full release. It is unknown as to why the Hobgoblin race was kept for Blurg.
Blurg will teleport away after repeated pickpocket attempts.