Nobleman of Extermination is a Normal 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, Nobleman of Extermination is Unlimited.
YGOPRODeck lists Nobleman of Extermination for these formats: GOAT, OCG GOAT, Duel Links, Speed Duel, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Nobleman of Extermination appears in Dark Beginning 1 (DB1-EN089) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Nobleman of Extermination is about $0.05 on Cardmarket (prices change frequently).
