Below is the Guide to help you locate all Deathbrand Armor set. Deathbrand armor parts are all light armor and you need to be at least level in 38 to get them.
Deathbrand Armor Set — Ancient Chest Locations Guide
Head to Haknir’s Shoal, which is located on the northern part of the map. Once you are in that are you will need to kill all pirates there and loot the captain’s bodies for the DeathBrand Treasure Map
Use the map to locate the area where the rest of the set are.
Enchantment: +100 Armor while wearing a full set of Deathbrand Armor and Waterbreathing.
Location: is located near the North of Windstone, the place called Haknir’s Shoal. This is a small Island in the frozen north of Solstheim. Basically is in the same place you got the map from
Location: Deathbrand Armor is located at Raven Rock (North of the Earthstone and northwest of RavenRock), look for the Ancient Chest by the water in a corner shore.
Location: The DeathBrand Boots is located in the area next to the Tel Mirthryn area Western side and inside the Ancient chest along the river’s Shore.
Location: DeathBrand Gauntlets Is located by the waterfall south of Bristleback Cave and also you will need to collect Gyldenhul Barrow Key
Once all Items collected you can now start Deathbrand Quest