Machine (機械 Kikai) monsters are powerful, and in some cases, fearsome to face in battle. They rely on high ATK as well as a variety of powerful effects, and they have some of the strongest Fusion Monsters in the OCG/TCG, that can be made even more powerful with the ATK-doubling ability of "Power Bond", "Cybernetic Zone", or "Limiter Removal". Most Machine monsters have DARK, EARTH, or LIGHT Attributes. In the Yu-Gi-Oh! (anime) first season, they have the special ability of immunity against all type of magic and Spellcaster attacks. Their general strategy varies, but they often have the ability to negate the effects of specific opposing cards and/or destroy them. Machine monsters also have four of their own Structure Decks: Machine Re-Volt, Machina Mayhem, Cyber Dragon Revolution, and Geargia Rampage Structure Deck.
Some of the numerous Machine archetypes include: "Jinzo", "Ancient Gear", "Cyber Dragon", "Gadget", "Geargia", "B.E.S.", "Vehicroid", "Ally of Justice", "Machina", "Karakuri", "Gimmick Puppet", "Mecha Phantom Beast", "Meklord" (which has the "Meklord Emperor" and "Meklord Army" sub-archetypes), and "Superheavy Samurai".
Notable Machine series include: "Cyberdark", "Cycler", "Gradius", "Machine King", "Gun Dragon", and "VWXYZ".
Due to their relative commodity, they are used by many characters in the anime and manga. Some of the more notable characters include Bandit Keith, Vellian Crowler, Syrus Truesdale, Zane Truesdale, Leo, Gong Strong and Yugo.