陰

When a card with an even mana cost is played, the attached card grants +1 mana. As the "Yin" half of the Yin-Yang gem set, it improves mana efficiency in decks built around even-cost cards. The more even-cost cards played in sequence, the more mana is returned, enabling more cards to be played within the same turn.

Unlocked by clearing Berserk Wood. The unlock may be recorded as "Yin Yang" and unified with the Yang gem unlock condition.

Maximize effect in decks stocked heavily with even-cost cards (costs 0, 2, 4, etc.). In builds that frequently play cost-2 cards, each play returns +1 mana, dramatically improving mana economy. Can also be paired with the Yang gem in a dual build covering both even and odd cost brackets.

Tier A — An Ultra Rare gem specialized for even-cost decks. Designing the deck around even-cost cards dramatically improves mana flow, allowing more cards to be played each turn. Becomes even stronger when used alongside the Yang gem.