Of all the Daedric Artifacts available in Skyrim, the Spellbreaker shield may be the one that is most worth the trouble to obtain. As the reward for the quest The Only Cure, Spellbreaker is unique in that it not only has a great armor rating for a Dwarven Shield, but it also casts a Ward spell when blocking, allowing it to negate the effects of spells and Shouts as well as blocking damage.
When combined with the Restoration perk Ward Absorb, the Atronach Alteration perks, the Atronach Standing Stone, and Ahzidal's Gauntlets of Warding, this allows you to absorb any magic that is fired at your character, though also means that you can't use any spells of yourself, such as the Flesh spells, healing spells, or certain Illusion spells such as Muffle.
Talk To Kesh
To begin the quest, you need to reach a minimum of level 10 to find Kesh at the Shrine to Peryite, located the dragon shrine northeast of Markarth. The quest can also be triggered by encountering a radiant Afflicted NPC, which will direct you to find Kesh as well. After talking to Kesh the Clean, you will be directed to find certain ingredients for Kesh: a Deathbell Flower, a Silver Ingot, Vampire Dust, and a Flawless Ruby. While the majority of these items are relatively easy to find, the Flawless Ruby is much more difficult and can be the sole reason why this quest can take much longer to complete than it otherwise should.
Find The Necessary Ingredients
Thankfully, only one of the ingredients needed is hard to find, while the others can all be found relatively easily. Deathbell Flowers can be obtained by delivering Farengar's Frost Salts to Arcadia in Whiterun, while being found in the wild around Morthal fairly consistently. Vampire Dust can be obtained by defeating any vampire enemy, though can also be bought from several Alchemy vendors, including Arcadia in Whiterun. Silver Ingots are a little harder to track down, though most general vendors or Smiths will sell them from time to time. You can also find the Transmute Mineral Ore spell in Halted Steam Camp, just behind Whiterun, that can turn Iron Ore into Silver Ore when cast.
Flawless Rubies, unlike regular Rubies, are very hard to find at low levels. You can increase your chances of finding a Flawless Ruby in chests by finishing the No Stone Unturned quest, which grants the player a passive buff that increases the chance to find any gemstones in chests. However, this quest is easily one of the longest and most difficult to complete in Skyrim, especially without a guide.
Although you can find a Flawless Ruby randomly throughout the game, one of the easiest ways to obtain one is to complete the Dark Brotherhood questline, as one is always found in the Emperor's Quarters on the Katariah, while another can be looted from Amaund Mottiere's corpse. You can also attempt to reset for one by completing a short errand for Harrald Law-Giver in Riften, where he gives you two randomized gems for completing his errand. While you can get a Flawless Ruby from this errand, Flawless gems appear much less frequently than regular variations and may take multiple resets before one is given.
Kill Orchendor
After returning to Kesh with the necessary ingredients, Peryite will appear and claim that his champion, Orchendor, has failed him and that you are needed to kill and replace him as Peryite's Champion. Once the dialogue with the Daedric Prince has ended, you will need to travel to Dwemer ruin Bthardamz, where Orchendor is bunkered down with dozens of Afflicted. This ruin can only be entered through this quest and you won't be able to get past the main door without first talking with Peryite.
After finding Orchendor, deep inside the dungeon, it becomes apparent fairly quickly that he is no pushover. Aside from being entirely immune to all spells, he is also able to teleport around the battlefield to avoid melee attacks and will be joined by several Dwemer automatons, including a Centurion.
The best way to approach this battle is from a distance with a bow or crossbow since you should be able to land at least one sneak attack on him before he decides to teleport around the battlefield. This way, you also avoid being flanked by Dwemer automatons while trying to fend him off, as they can deal quite a lot of damage if left unchecked. Once Orchendor is defeated, loot his corpse and take the key to the Bthardamz elevator, which will prevent any longwinded backtracking, and return to Peryite for your reward.
Return To Peryite
Upon returning to the Shrine to Peryite, inhale the fumes once again to talk to the Daedric Prince, where you will have to have a short conversation with them congratulating your ability to kill people who were well on their way to a long and painful death before the quest is completed. Once the dialog is over, you will be given Spellbreaker as a reward, a shield with a base armor rating of 38, even higher than a Daedric or Dragonplate Shield. Once you have this shield, there is almost no reason to use any other shield in the game, with the only exception being if you want to use a shield with a unique effect, such as the Targe of the Blooded or Auriel's Shield.