Dark City is a Field Spell Card.
Spell Cards are usually activated from the hand on your turn unless their type gives another timing window.
On the current TCG and OCG Forbidden & Limited lists tracked here, Dark City is Unlimited.
YGOPRODeck lists Dark City for these formats: Duel Links, Speed Duel, Common Charity, Edison, TCG, OCG, Master Duel.
Dark City belongs to the Destiny HERO archetype—use that tag when searching for engine pieces and tech options.
A listed print of Dark City appears in Duelist Pack: Aster Phoenix (DP05-EN019) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Dark City is about $0.05 on Cardmarket (prices change frequently).
