Gaia Knight, the Force of Earth is a Warrior Synchro Monster with Attribute EARTH, Level 6, ATK 2600, DEF 800.
Synchro Summons need Tuners plus non-Tuners whose Levels equal the Synchro Monster’s Level.
On the current TCG and OCG Forbidden & Limited lists tracked here, Gaia Knight, the Force of Earth is Unlimited.
YGOPRODeck lists Gaia Knight, the Force of Earth for these formats: Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
Gaia Knight, the Force of Earth belongs to the Gaia The Fierce Knight archetype—use that tag when searching for engine pieces and tech options.
A listed print of Gaia Knight, the Force of Earth appears in Advanced Demo Deck Extra Pack (DEM4-EN008) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Gaia Knight, the Force of Earth is about $0.19 on Cardmarket (prices change frequently).
