Warden
Shadow IslesField in combat: 5 unique star levels of Shadow Isle + Req. lvl 8
The best build for Thresh is Shadow Isle Warden (S tier). Thresh is a 5-cost champion with the following traits: Warden, Shadow Isles. Recommended items for Thresh are: Bloodthirster, Morellonomicon, Void Staff. Champion quest: Field in combat: 5 unique star levels of Shadow Isle + Req. lvl 8 Thresh also features in these builds: Ruined King.
