Vengeful Servant is a Equip 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, Vengeful Servant is Unlimited.
YGOPRODeck lists Vengeful Servant for these formats: Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Vengeful Servant appears in Crimson Crisis (CRMS-EN046) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Vengeful Servant is about $0.10 on Cardmarket (prices change frequently).
