Anyone know where the reaper's lair is in the soul cairn? Seen a lot of conflicting directions in other threads.

Once you enter the Soul Cairn follow the main path until you walk through the big wall. Look to you right for the Spire with the floating rocks and purple stuff around the top. Over next to that. The summon Wrathmen conjuration book is also under an altar thing next to it.

Exactly what is the purpose of the lair?