Black Waters, Broken Tombs is an off-screen companion adventure in Pillars of Eternity.
In-game description[]
The pitch:
At the southeastern edge of Eir Glanfath, the isolated town of Airana's Tears sits on the northern shore of the Lake of Drowned Tombs.
Lately, a strange phenomenon has turned the lake's clear waters black. Stranger still, the town's stone tombs have been breaking open from the inside, the skeletal occupants slowly marching to the water's edge and into the depths.
The conclusion:
After several futile nights of waiting, [Companion Name] finally discovered the origin of the lake's black waters: the cean gŵla of a witch who had settled in Airana's Tears over a century ago. Locals had accidentally plowed up her burial plot. Her remains had slid into the lake during a fierce storm.
The spirit, previously content to haunt the field, had begun calling her old neighbors down into the lake with her. With the help of the locals, [Companion Name] was able to put the spirit to rest.
Most of the corpses were able to be returned to their tombs, but not all of the tombs could be reassembled. [Companion Name] brought back a piece of one mystery tomb as a souvenir.