yugioh cards link Konami KON547359 Cyberse Structure Deck Card, Multicoloured : Toys & Games Code of the Duelist Card type Linkross - Yugipedia

I think the cards extreme value comes from a combination of uniqueness, historical importance, and collector mythology

Soul Release Cards like Kycoo are great for getting rid of your opponents cards in the graveyard But even with Kycoo out, its not always possible to inflict battle damage

C Common SH Shatterfoil Fighting Spirit X SPELL Equip The equipped monster gains 300 ATK for each monster your opponent controls

Legality depends on the tournament format -- Subterror Behemoth Ultramafus can be legal in some formats and banned or restricted in others

C Common Branded Sword X TRAP Banish any number of "Branded" Spells/Traps from your GY

Decks With This Card Recent public and tournament decks using Nightmare Hands