Thassa, Deep-Dwelling

📖 How to build Thassa, Deep-Dwelling

Thassa, Deep-Dwelling is an indestructible enchantment that usually sits on the battlefield as a non-creature. Its end-step trigger exiles up to one other creature you control and returns it under your control, so creatures with enter-the-battlefield effects get reused every turn. Its {3}{U} ability taps another target creature, which lets you remove a blocker or stop an attacker at instant speed. The plan is to build a value engine that repeats ETB effects while controlling the board with taps.

Build around blue creatures with strong enter-the-battlefield effects, since the end-step trigger is the engine. Add enough blue permanents to push devotion to five, which turns Thassa into a creature and lets it attack or block. Blue interaction such as Counterspell, Negate, and Arcane Denial protects your engine, and card advantage from Rhystic Study or Mystic Remora helps fund the {3}{U} tap ability each turn.

Thassa's weaknesses are its mana cost and dependence on creatures. The blink only works on creatures you control, so a board with few creatures gets little value, and the tap ability costs four mana every time it's used. Thassa is only a creature when devotion is at least five, so it can't rely on being a threat. Indestructible stops destruction, but exile and bounce effects still work against it.

Deck guide written with AI assistance based on the card's rules text.