• While "Mask of Restrict" is active, you cannot Tribute "Kiryu" because "Mask of Restrict" prevents all Tributing, including Tributing Equip Spell Cards.

• If you Tribute "Kiryu" while it is equipped to "Dark Blade", you cannot then use "Super Rejuvenation" and count "Kiryu" as a Dragon-Type monster.

• If you Tribute "Kiryu" while equipped to "Dark Blade", "Dark Blade" no longer gets the ATK increase from "Kiryu" as it is no longer equipped with it.

Mentions in Other Rulings

• Combination Attack: If "Dark Blade", equipped with "Kiryu" and "Twin Swords of Flashing Light - Tryce", attacks twice using "Twin Swords of Flashing Light - Tryce"'s effect, then you use "Combination Attack" to detach "Kiryu" from "Dark Blade", both monsters can attack again once each. "Dark Blade" cannot attack another 2 times because it has already attacked twice.

• Twin Swords of Flashing Light - Tryce: If "Dark Blade" equipped with "Kiryu" is also equipped with "Twin Swords of Flashing Light - Tryce", and attacks twice, and "Kiryu" is then "detached" with "Combination Attack", "Dark Blade" can attack 1 more time (not 2 more times).

• In order to attach a Union Monster to another monster, you must first have the Union Monster as a monster on the field. So you must play the monster normally, then you can attach it. You cannot play a Union Monster as an Equip Spell Card directly from your hand.^[32]

• You can Summon a Union Monster and attach it to another monster right away. You cannot attach a Union Monster and detach the same Union Monster during the same turn, unless a card effect specifically allows it (such as "Combination Attack").^[32]

• Union Monsters only grant their special effects to a monster when equipped to that monster using the Union Monster's effect. So if "Relinquished" equips itself with a Union Monster, it gains none of the Union Monster's bonuses. Also, if "Union Rider" equips itself with a Union Monster, "Union Rider" gains none of the bonuses. The Trap Card "Formation Union" is considered to equip the Union Monster 'by its own effect' so the bonuses do activate.^[32]

• A Union Monster that is attached to a monster is treated as an Equip Spell Card and can be destroyed with "Heavy Storm", etc. You can use "Magic Reflector" to place a counter on an equipped Union Monster and, if the equipped monster would be destroyed in battle, you can remove the counter instead so neither the equipped monster nor the Union Monster are destroyed.^[32]

• A monster can only be equipped with 1 Union Monster at a time, but can still be equipped with other Equip Spell Cards such as "Axe of Despair", etc.^[32]

• If an equipped monster is taken by the opponent (such as with "Snatch Steal"), the Union Monster remains where it is, although it is still equipped to the monster, and the player who controls the Union Monster can detach it and it is Special Summoned to that player's side of the field. (So if I have "X-Head Cannon" equipped with "Z-Metal Tank", and my opponent uses "Snatch Steal" on "X-Head Cannon", on my next Main Phase I can detach "Z-Metal Tank" and it is Special Summoned onto my side of the field because I still control it.)^[32]

• If a Union Monster turns into an Equip Spell Card, or reverts back into a monster, effects are reset. For example, if I use "Call of the Haunted" to Special Summon a Union Monster, then attach it to another monster, it is no longer affected by "Call of the Haunted" (which remains on the field meaninglessly and, if destroyed, does not destroy the Union Monster). If I use "Limiter Removal" on a Union Monster, and equip it, it is not destroyed at the end of the turn, and if I turn it back into a monster its ATK is no longer doubled.^[32]

Mentions in Other Rulings

See also Card Rulings:Formation Union, as all of its rulings mention "Union Monsters".

• Anteatereatingant: You can send a Field Spell Card to the Graveyard as part of the cost to Special Summon “Anteatereatingant”. You can also use a Monster Card treated as an Equip Card, such as a Union Monster or a monster equipped to “Relinquished ^[sic].

• Cocoon of Evolution: If "Cocoon of Evolution" is Summoned or Set it is treated as a monster, if played as an Equip Spell Card it is treated as an Equip Spell Card as long as it remains on the field and could be destroyed with "Mystical Space Typhoon". Once on the field it cannot be switched from monster to Spell Card or vice versa. "Cocoon of Evolution" is NOT a Union Monster.

• Collected Power: If multiple Union Monsters are going to be equipped to 1 legal target monster by "Collected Power", you select 1 of them and equip it to the target monster, and the other Union Monster Cards are destroyed.

• Combination Attack: Both the equipped monster and the Union Monster can attack after "Combination Attack" is used, assuming the Union Monster was Special Summoned in face-up Attack Position.

• Combination Attack: You can attack with a Union Monster, use "Formation Union" to equip it to a monster, attack with the equipped monster, activate "Combination Attack" to detach the Union Monster, and attack again with the previously-equipped monster and with the Union Monster.

• Combination Attack: If the player who would control the Union Monster already has 5 monsters on the field, "Combination Attack" cannot be activated.

• Cyber Phoenix: While you have “Cyber Phoenix” on the field in Attack Position, “Heavy Mech Support Platform” can be equipped to a Machine-Type monster on your side of the field but all of its effects are negated. It will not increase ATK, or be destroyed in place of the equipped monster, and it cannot be unequipped & Special Summoned by its own effect. (The Machine-Type monster can still only be equipped with 1 Union Monster at a time, because that is a condition, not an effect).

• Divine Wrath: You can activate "Divine Wrath" when any Union Monster activates its effect to equip itself to another monster, because that is an Ignition Effect. However, you cannot activate "Divine Wrath" when a Union Monster Special Summons itself back as a monster, because that is an effect of an Equip Spell Card.

• Frontline Base: If you have multiple "Frontline Bases", you can Special Summon 1 Union Monster for each.

• Heavy Mech Support Platform: Note that "Heavy Mech Support Platform" is different from other Union Monsters in that its last sentence is applied if the monster it is equipped to is destroyed (period), not just when the monster is destroyed as a result of battle. This extra effect does not apply to previous Union Monsters.

• Jowls of Dark Demise: If you take control of a Union Monster with "Jowls of Dark Demise", and equip it to your monster, control of the Union Monster Card does not return to your opponent at the end of the turn because it is an Equip Spell Card.

• Lightwave Tuning: If a LIGHT Union monster is also treated as a Tuner monster with "Lightwave Tuning", when the Union monster is equipped to another monster it is no longer treated as a Tuner monster. If it is Special Summoned during the same turn, it is still not treated as a Tuner monster.

• Mage Power: "Mage Power" includes itself, Field Spell Cards on your side of the field, and monsters acting like Equip Spell Cards, such as Union Monsters.

• Magic Reflector: If you use "Magic Reflector" to place a counter on a Union Monster that is an Equip Card, and the Union Monster would be destroyed instead of the equipped monster, remove the "Magic Reflector" counter from the Union Monster instead, and the Union Monster is not destroyed.

• Spell Counters: You do not place a Spell Counter on this monster when you attach or detach a Union Monster because that is not the activation of a Spell Card.