Tenacity of the Monarchs 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, Tenacity of the Monarchs is Unlimited.
YGOPRODeck lists Tenacity of the Monarchs for these formats: Common Charity, TCG, OCG, Master Duel.
Tenacity of the Monarchs belongs to the Monarch archetype—use that tag when searching for engine pieces and tech options.
A listed print of Tenacity of the Monarchs appears in 2015 Mega-Tin Mega Pack (MP15-EN232) at Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Tenacity of the Monarchs is about $0.34 on Cardmarket (prices change frequently).
