Katarina's Ornamental Ring

Part of a set of four. Used inside the Midden Dark on a special daedric relic to release the Daedra Velehk Sain. He requests that you release him. You have two choices: 1: Release him and recieve the whereabouts of his treasure 2: Attempt to banish him to Oblivion. (this does not work making him hostile) He says trying to kill him won't be easy, when in fact it takes very little to kill him. Upon death he is carrying very little, just light armor, a scimitar or two, and his Daedra heart. The treasure is located near Winterhold.