The Horns of the Reach Add-on for The Elder Scrolls Online: Tamriel Unlimited has 6 achievements worth 220 gamerscore.
Defeat all mini-boss and boss enemies in Bloodroot Forge.
Defeat all mini-boss and boss enemies in Falkreath Hold.
Complete Veteran Bloodroot Forge without ever touching the lava flowing through the Sanguine Veins.
Never be personally struck by siege weapon fire in Veteran Falkreath Hold.
Use Galchobhar's Mantle Breaker to dissipate a Fire Shalk's Lava Ball in Veteran Bloodroot Forge.
Complete Veteran Falkreath Hold and Veteran Bloodroot Forge.