Blood Ring Location - Morrowind
Location: Dagoth Ur, Lower Facility
Requirements: Levitate/Jump spell to navigate terrain near Dagoth Ur
Video: How to get the Blood Ring
The Blood Ring is an Artifact obtained from Dagoth Gilvoth who is found inside Dagoth Ur, the final dungeon in the game. You are tasked with visiting this dungeon during the final quest of the game, The Citadels of the Sixth House, however since this is an Elder Scrolls game you can come here and kill this enemy whenever you want regardless of the quest.
In order to gain entry to Dagoth Ur you'll need to use the Dwarven Crank south of the entrance. There are some pictures on the UESP wiki that may help. Here is a brief video I made showing you how to get inside if you'd prefer a video.
Dagoth Gilvoth is found in the Lower Facility portion of Dagoth Ur, you'll have to go through the Outer and Inner Facilities to reach this area. Once you're in the Lower Facility finding him won't be difficult since it's a rather linear path.