Gem-Knight Ruby is a Secret Rare Fusion Monster card from Yu-Gi-Oh! (Hidden Arsenal 5: Steelswarm Invasion, HA05). Current market price: $0.17.
Secret Rare
Hidden Arsenal 5: Steelswarm Invasion (HA05)
Card Text
"Gem-Knight Garnet" + 1 "Gem-Knight" monster
Must first be Fusion Summoned with the above Fusion Material Monsters. Once per turn: You can Tribute 1 face-up "Gem-" monster; this card gains ATK equal to the Tributed monster's ATK on the field, until the End Phase. If this card attacks a Defense Position monster, inflict piercing Battle Damage to your opponent.
