How to get Ice Blade of the Monarch - Elder Scrolls: Morrowind
Video: How to get Ice Blade of the Monarch
Ice Blade of the Monarch is obtained from Llaren Terano inside of Rotheran, a dungeon to the south of Dagon Fel. Obtaining this blade is part of the Ice Blade of the Monarch Side Quest given to you by the Imperial Cult, you'll be able to keep the weapon when you finish the quest.
You don't need to be on this quest to obtain the weapon from Llaren Terano, much like in all Elder Scrolls games you can technically come here at any time and collect the weapon. It's recommended though that you don't free Adusami until the Imperial Cult sends you here during the quest - if you do then you won't receive the reward for this quest when it comes time to do it for the Imperial Cult.