Undermountain (LGR)

Undermountain is an adventure module from the RPGA Legacy of the Green Regent campaign.

Plot
A legendary manifestation known in the Delimbiyr Vale is heard singing inside the Yawning Portal of how Otar the Green Regent, whom the party has been tasked to find, is trapped in Undermountain by cyricists. Since Otar is the reason the party is in Waterdeep, they descend into the massive dungeon to find and rescue him.

"The most famous battlefield in which to earn a reputation as a veteran adventurer— and the best-known grave of heroes in Faerûn."

- Elminster of Shadowdale