The Orsinium Add-on for The Elder Scrolls Online has 6 achievements worth 220 gamerscore.
Conquer all challengers and earn the title of Maelstrom Arena Champion.
Complete 27 quests in Wrothgar.
Complete Wrothgar's main quests.
Complete quests, defeat bosses, and explore delves to become the Hero of Wrothgar.
Collect all 20 relics for the House of Orsimer Glories.
Conquer all challengers in Veteran Maelstrom Arena.