Introduced in set:
The names of the Unknowns in Episode 1 all refer to fictitious or real-world espionage personalities.
Unknown creatures originally featured the Kanji of 偽りの名 (Itsuwari no Na), which means "False Name". コードネーム (Kodonemu) is written in katakana above this text, meaning Codename.
DMR-06 and DMX-11 added multiple new naming procedures for Unknown creatures.
- Light creatures with the Angel Command race have 真実の名 (Shinjitsu no Na) meaning "Truth Name".
- Above it, トゥルーネーム (To~urūnēmu) or "Truename" is written.
- Many of them also contain レオ (Leo) and オレ (Ore).
- Light creatures with the Demon Command race have 偽りの羅刹 (Itsuwari no Rasetsu) meaning "False Evil Spirit".
- Above it, コードファイト (Kōdofaito) or "Codefight" is written.
- Light evolution creatures with the Demon Command race have 偽りの羅刹 (Itsuwari no Akuma Kami) meaning "False Devil God".
- Above it, コードデーモン (Kōdodēmon) or "Codedemon" is written.
- Darkness creatures with the Angel Command race have 偽りの星 (Itsuwari no Hoshi) meaning "False Star".
- Above it, コードナイト (Kōdonaito) or "Codenight" is written.
- Fire creatures with the King Command Dragon race have 偽りの王 (Kōdokingu) meaning "False King".
- Above it, コードキング (Kōdokingu) or "Codeking" is written.
- Fire creatures with the Armored Dragon race include ラゴン (Ragon) in their card name.
- Nature creatures with the Wild Veggies race have 偽りの大菜王 (Itsuwari no dai saiō) meaning "False Large Vegetable King".
- Above it, コードベジタブル (Kōdobejitaburu) or "Codevegetable" is written.
They later featured on cards in all of the civilizations as well as on Zero creatures.
Unknown creatures have a race dedicated to helping them, the Unnoise.
|Support Creature:||Card Effect:|
|King Acer||Your Unknown creatures cost 1 less to summon.|
|Messa Danjiri Dragon||Your Unknown creatures cost 1 less to summon. All of your Unknown creatures in the battle zone have "speed attacker".|
|Necrodragon Onbashi Raon||Your Unknown creatures cost 1 less to summon.|
|Yosakoi, Leader of Spirits||Your Zenith creatures cost 1 less to summon.|
|Zenith Symphony, Secret Zenith|| Attack Chance: Unknown |
"You may summon a creature with both the Zenith and Unknown races for no cost. At the end that turn, return that creature to your hand."
|Zondag Giant||Your Unknown creatures cost 1 less to summon.|
|Yosakoi, Leader of Spirits||Your Unknown creatures cost 1 less to summon.|
|Codename Hungry Elegance||You may summon Unknowns from your mana zone.|
|Codename Sword-Flash Ragon||When this creature is tapped for the first time of a turn, reveal the top card of your deck. If it's an Unknown, put it into your hand, and you may untap this creature.|
|Menkoikoi, Martyrdom Guardian||Ultra Saver: Guardian and Unknown (When 1 of your Guardians or Unknown would leave the battle zone, you may destroy this creature instead.|
|Mouse Sittrain, Express Machine||When you put an Unknown into the battle zone, you may draw a card.|
|Thumbtack Man||When you put an Unknown into the battle zone, you may destroy this creature. If you do, destroy one of your opponent's tapped creatures.|
|Shibake Lupia||When you put an Unknown into the battle zone, destroy one of your opponents creatures with power 4000 or less.|
|Katchikachi Itchikatchizu||When you put an Unknown into the battle zone, you may add a creature from your mana zone as a new shield into the shield zone face down.|