Basmueth the Cruel

Big boss monster for my D&D campaign! Millennia ago, a great knight, Lotan, wrestled him to a standstill, but could not kill him, so the knight begged his lover to throw her spear, knowing full well it would kill them both, for his heart was right above the beast's. She did so, slaying her lover for the greater good. She was pregnant, and she and her daughter became the founders of the Midwives, an order of female paladins dedicated to childbirth, tending to the sick, caring for orphans, and killing the fuck out of evil shit.

A few decades ago, in game-world time, the Midwives were destroyed by a rival inquisitor force, and most of the few survivors fled to Lotan's Grave, their most ancient shrine, deep in the undercity. Little did they know that Basmueth's spirit, his hate concentrated over the millennia, awaited them, ready to strike while they were at their most vulnerable...