Eternal Hunt is a craftable set. When you use Roll Dodge, you leave behind a rune that detonates when enemies come close, dealing 8125 Poison Damage and immobilizing them for 1.5 seconds.
Eternal Hunt is part of the Thieves Guild DLC. The crafting station is located in Hew's Bane (The Lost Pavillion). You can craft any armor, jewelry or weapon of this set in any motif style you know, as long as you have 9 traits researched (per item). You can trade crafted set items to other players. Each set item becomes bound on equip.