Bujinfidel is a Normal Trap Card.
Trap Cards are normally Set first and can be activated on a later turn, often in response to an action.
On the current TCG and OCG Forbidden & Limited lists tracked here, Bujinfidel is Unlimited.
YGOPRODeck lists Bujinfidel for these formats: Duel Links, Common Charity, TCG, OCG, Master Duel.
Bujinfidel belongs to the Bujin archetype—use that tag when searching for engine pieces and tech options.
A listed print of Bujinfidel appears in 2014 Mega-Tin Mega Pack (MP14-EN108) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Bujinfidel is about $0.06 on Cardmarket (prices change frequently).
