Deckie

Decky is an animate deck box of Joe Kirifuda.

Appearance
Decky is a ordinary white and black deck box. He have a face, a red bowtie and sometimes sprouts out legs and arms when needed. After Joe named the unknown civilization created Jokers, Decky gains a green 'J' mark on his body.

Personality
Decky is quite energetic and knowledgeable about the Duel Masters game. At times he have to act as an ordinary deck box in order not to get noticed or found out.

Decky's abilities to create cards was limited, which was shown when he tells Joe that it was impossible to create cards based by dragons. This means that Decky's abilities was linked to the creature world and its current state. He also can swallow the card itself to bring the spirit back to the creature world.

Decky was capable of seeing through the disguise of creature spirits even if the spirit itself is in its human form.

Anime
Decky was from the creature world. At that time, the balance in the creature world was starting to crumble. Hoping to find a Duel Master, Decky went to Earth.

Duel Masters (2017)
He first landed right at Joe's face from a comet swarm. He was brought to Joe's home to be cleaned and almost strangled him to death because Joe worn him by the collar and he was moving along with his rope strangling him. When Joe took him he claimed he had the ability to create cards, so Joe stuck a drawing of Jolly the Johnny on his mouth and fed him water, then stuck his rear with a key which caused Decky to spit out a real life Jolly the Johnny. However it began shooting in Joe's room so Joe used Decky to turn the creature into a card before it could do more damage. Decky was surprised itself that the cards created are not from any of the 5 main civilizations. Joe then proceeds to turn all of the drawings in his room into cards and construct a deck using Decky.

In his duel against Shacho, Decky told him how to duel.

At the end of the day, it was shown that Decky's insides is a portal to the creature world, with Decky admitting that he had hid some secrets from Joe about the state of the creature world.

When Joe was almost late for school, Decky creates a creature card Chotto Q from Joe's drawing of the said creature. Decky then pours hot water onto the card, causing it to materialize again, but ended up getting a pecking from the said creature. As Joe made it in time to school with the help of Chotto Q, Decky tells Joe to play dumb as Team Usagi had spotted them using a creature spirit. Decky also recognizes Joe's mother Lulu Takigawa when Joe heads to the bar she owns.

When both Joe and Decky overhears that there is another pro duelist, Decky don't believe in the statement as he considers Joe as the Duel Master. The pro duelist was then revealed to be Joe's childhood friend Kira. After Joe loses to Kira, he tells Decky to create a card based by a dragon he drew a few years ago when his father was still around. Decky replies that it was impossible as all of the dragons in his world were wiped out and only exists in legends. However, he mentions that the creatures in his world are searching for any existing dragons.

In the night, Decky was worried about the frequent arrivals of creature spirits to the human world due to the state of the creature world. This was proven true when a creature spirit Shizenseijin in his human form was left stranded in the human world. To stop the spirit who had taken Joe's classmate Urara Kamomo, Decky projects a tower Duel Field to settle the score in a duel. However, the Duel Field has the same properties as some of the dangerous duels that the previous generations had faced; the duelist himself sustain damage. When Jolly the Johnny was about to deal a finishing blow on Shizenseijin, Joe commanded him to stop, much to Decky's annoyance. Decky receives 'punishment' from Joe, which is to convert Shizenseijin back to its card form. Decky then swallows the card in order to bring the spirit back to the creature world.

Trivia

 * He shares the same voice actor as Passionate Narrator from the Versus Saga of the anime.