How to get Ebony Mail - Elder Scrolls: Morrowind
Ebony Mail is arguably the best chest armor you can get in the game despite it being medium armor. This item is traditionally given to you as a reward for finishing all of Tholer Saryoni's quests and becoming the Patriarch of the Tribunal Temple. Tholer Saryoni asks you to complete the Pilgrimage of the Four Corners which involves visiting 4 Daedric Shrines then the Mount Assarnibibi Shrine which is the one that rewards you with this armor.
Despite this item technically being a quest reward - you don't actually need to be affiliated with the temple to get it nor do you need to complete these quests to get it. You can visit all 4 of the Daedric Shrines then go to Mount Assarnibibi and get the armor without having the pre-requisite quests. If you'd like to see the full write ups with pictures that I have of the quests required to get this item check my Tholer Saryoni's Tribunal Temple Quests page for more information.
Below are brief versions of the aforementioned write ups.
Pilgrimage #1: Take 4 Daedra Hearts to the Statue of Malacath west of Dagon Fel
Pilgrimage #2: Interact with the Statue of Mehrunes Dagon inside of Ald Sotha
Pilgrimage #3: Go north of Suran and into the dungeon of Bal Ur; interact with the Statue of Molag Bal inside
Pilgrimage #4: Venture to Ald Daedroth on the large island east of Dagon Fel. Retrieve the Gambolpuddy Glove from inside the shrine and then interact with the Statue of Sheogorath
Every time you interact with one of these shrines you will get a Journal entry. Once you've gotten the 4 Journal entries for interacting with each shrine you'll be able to interact with the Mount Assarnibibi Shrine and receive the Ebony Mail as your reward.