When a person finds and becomes Buddies with a monster (normally by finding a Buddy Rare card), they are given a Core Deck Case by a Buddy Police officer. Core Deck Cases allow the user to "Luminize" their decks, allowing them to have a Buddyfight at any time together with their monsters, as well as using their Buddy Monster's abilities (such as flying).
When activated, Core Deck Cases transform into "Core Gadgets" with different forms.
As explained by El Quixote, the Core Gadget takes the shape of an object that reflects a fighter's inner hopes and dreams, either taking the shape of a personal symbol of strength for that fighter, like the Sun Belt for Gao, reflecting his dreams and ambition of becoming the Sun Fighter, or the Dragon designed Lance for Noboru, reflecting his straightforward personality and ambitions to become a Dragon Knight, or they take the shape of an object reflecting a person's inner wants and needs such as Tasuku's Armor while as the Purgatory Knight to hide his true identity from others.
Core Deck Cases seem to know who their legitimate owners are, and if used by someone else they will keep the shape that represents their real owners. If a fighter has more than one Core Deck Case, they will all take the same form, even if they are Dark Cores.
Core Gadgets automatically draw cards for players when their crystal is touched, shuffle their hands, and summon the monsters in battle while an automatic voice guides the player during their respective turns. Most, if not all, Core Gadgets have the ability to levitate as well. Without any noticeable input, these Core Gadgets can remain at the fighter's side within hands' reach and can automatically track their movement to adjust accordingly, such as when flying in the air due to a Buddy Skill. These Core Gadgets can also levitate back towards a player's side such as when they're deliberately thrown away by them.
Players who do not possess their own Core Deck Case can use an all-purpose Core Gadget to luminize their decks when fighting against someone who does own a Core Deck Case.
When a Core Gadget uses Future Force, the crystal becomes red.
Known Core Deck Cases
Any fighter without a Core Deck Case of their own
|Multi-Purpose Core Gadget||This core gadget is used within establishments like Castle for those without a Core Gadget of their own to Luminize their cards.|
|Ageha Gokuraku||Winged Compact|
|Akaoni Konmae||Red Fundoshi||When it was first revealed, Jack and Tasuku laughed at its appearance, while the other people watching the match are stunned or shocked by it.|
|Aooni Konmae||Blue Fundoshi|
When activating his Buddy Skill, Ban is capable of riding his Core Gadget similar to a hoverbike, allowing him to traverse large distances with ease.
It comes equipped with a handlebar tow that allows him to pull other people while flying, similar to parasailing.
|Brutal of the Martial Arts|
|Buddy Police||Hover Disc Parts||During the battle against Yamigedo, it was show that the members of the Buddy Police all possess the same core gadget.
Takihara's core gadget was destroyed by Rouga after he destroyed a Buddy Police Barrier, but eventually replaced with a new one.
Captain Answer (Owner)
Genma Todoroki (Temporarily)
This gadget is capable of firing Luminized card "bullets" at opponents or to call monsters from the deck installed in it. It also allows the user to Transform into "Captain Answer" even outside a Buddyfight.
Tasuku borrowed this Core Gadget from Neginoyama when he raided Disaster's base, but was returned after joining them. He didn't use it in his buddyfights with Disaster's members though.
It briefly came into Genma's possession when Negonoyama lost it after his interaction with Kemura, allowing Genma to impersonate Captain Answer for his Buddyfight with Shido.
|Castle Store Manager||Helmet|
|Demon Inzaidi||Gem (Both Destroyed)||
Inzaidi possesed two of these Core Gadgets, keeping the 2nd as a backup incase the first was destroyed.
Both were destroyed after losing to Tsurugi Takihara and Captain Answer.
They have a similar design to the Multi-Purpose Core Gadget.
|Devil Destroy Bigmachine||Dumbbell|
|Totsuo Doai||Moai||Using his Buddy Skill, Doai is capable of riding the Moai statue as an improvised hoverbike, allowing him to achieve great speed to ram into other objects.|
Sun Belt (Destroyed)
When drawing from it or making his Mighty Sun Fighter speech, it rotates sideways.
It was destroyed after Gao suffered his first loss to Ikazuchi, and was replaced with a Neo Core Deck Case.
|Genma Todoroki||Arm band|
|First Knight of the Apocalypse, Gratos||
|The Hanako In The Toilet||Orb|
|Iron Claw Ikarino||Staff||This Core Gadget doesn't seem to include a crystal.|
|Ivan Shikakevich Wanaski||Snowmobile|
|Sir James Knightman||Shield|
|Jin Magatsu||Shuriken Holster|
|Kanata Ozora||Ball||When the Core Gadget is summon, his outfit changes.|
|Keisetsu of the Sword Arts||Skateboard|
|Long Daiakuji||Yin & Yang|
Magoroku Shido (Owner)
This was used by Shido for his beginning matches in the first season. When his ties with Disaster was revealed, he replaced it with his Dark Core Gadget.
By Buddyfight 100, he returns to using it once more.
|Mukuro Shigamine||Top (Destroyed)||
Spins while in use.
Noboru used this as an impromptu throwing weapon to reveal Tasuku as the Purgatory Knight.
|Paruko Nanana||Microphone||Paruko uses this to give the play-by-play on the Buddyfights where she is the commentator, even using it during her own Buddyfights with other people.|
|Raremaro Tefudanokimi||Kusudama||When using his Buddy Skill, Raremaro holds onto the tassels to float away rather then levitate on his own.|
Rouga used this whenever he was in public while at Aibo Academy.
After losing to Gao and transferring to Sengoku Academy, he replaced it permanently with his Dark Core Gadget.
|Sayuri Gotsurugi||Hair Pin|
|Shosetsu Kirisame||Sword Sheath||Shosetsu keeps Durandal within the sheath and only draws it out whenever he equips it.|
|Shura Gokumon||Skull Pauldron|
|Sofia Sakharov||Jewel||Sophia can draw cards from it without needing to physically touch the crystal, instead she seems to draw cards telepathically|
|Suzuha Amanosuzu||Dessert Stand||
Suzuha normally has Sebastian at her side during matches to hold her gadget.
While under the control of a Hundred Demons, it is shown to float like most Core Gadgets.</span>
|Star Pulsar (Replaced)||
It remained as Tasuku's Core Gadget for much of the 1st Season until he joined Disaster.
While Tasuku was with Disaster, it fell into Kiri's hands after raiding Disaster's base to free the captive Buddy Monsters, which he then gave to Gao.
It was returned to Tasuku's possession after he left Disaster.
Interestingly enough, this is the only Core Gadget to be called by an actual name and the only non-Neo Deck Case to have a red crystal.
|Togari Togeyama||Shoulder Pad|
|Unknown Criminal||Hammer (Destroyed)||It was destroyed after the criminal was defeated by Tasuku.|
|Wataru Kageo||Top Hat|
|WBC Japan Cup Participant||Sword|
|WBC Japan Cup Participant||Football|
|WBC Japan Cup Participant||Belt|
|WBC Japan Cup Participant|
|WBC Japan Cup Participant|
|WBC Japan Cup Participant||Gem|
|WBC Japan Cup Participant||Diamond|
|WBC Japan Cup Participant||Bracelet|
|WBC Japan Cup Participant||Bracelet|
|WBC Japan Cup Participant||Platform|
|Zanya Kisaragi||Wakizashi||Zanya is shown drawing the blade whenever he activates his Secret Sword Impacts.|
Dark Core Deck Case
A "Dark Core Deck Case" gives its owner the ability to use Disaster Force. The user can become more malevolent and power-hungry if they can't control the Dark Core's powers. Anyone who comes into contact with a Dark Core becomes negative, sinister and darker under its influence. They can also be used to possess others, as seen with Doai. It has also been shown to occasionally surprise the user and activate Disaster Force without their permission.
All known Dark Cores so far are black colored when inactive and have an eye-like figure over the crystal. When luminizing using Dark Core Deck Case, the luminize is called "Dark Luminize"
According to Kyoya, they are developed by his financial group after Disaster Force was "accidentally discovered". An additional side effect of using Disaster Force is that it fuels a portal to Darkness Dragon World, allowing monsters from it to invade Earth.
A deck case themed after the Dark Core was released.
|Bolt Fuchigami||Mini Yamigedo "Spirit Form"||
This is the only Dark Core Gadget to seemingly not to have been made by Kyoya Gaen.
Considered a Dark Core Deck Case because it can "Dark Luminize" cards.
|Davide Yamazaki||Pendant||It attaches to the side of his choker|
|Elf Kabala||Compact||Kabala has added a feature to his Core Gadget that allows him to use it in a similar fashion to a remote control to manipulate all of the monsters that Disaster had captured so far.|
|Kiri Hyoryu||Snowflake (Destroyed)||It was destroyed after Kiri lost to Gao within Disaster's HQ.|
In Buddyfight 100, Shido has returned to using his standard Core Gadget.
|Shosetsu Kirisame||Sword Sheath (Destroyed)||After Shosetsu lost control of the Disaster Force and went on a rampage, it was quickly destroyed by the efforts of Tasuku.|
In Buddyfight 100, Sofia use a Normal ore Gadget.
Tasuku Ryuenji (Disguised as the Purgatory Knight)
Purgatory Knight (Copy made by Armordeity, Dynamis)
A sentient copy of the gadget was created by Armordeity, Dynamis to test Tasuku and Jack, to see if they were worthy of utilising Star Dragon World. It is unknown if this copy was also a Dark Core Gadget.
Terumi Kuchinawa (Previous Owner)
It was taken by Sofia after she erased Terumi's memories.
Neo Deck Case
Nothing much is known about them other than the fact that it is quite new and so far only Buddy Police Officers have them.
One characteristic that differentiates them from standard Deck Core Cases is that the crystal is colored red, similar in appearance to when the standard Cases utilises the Future Force.
|Gao Mikado||Sun Belt|
Neo Star Pulsar
|Sixth Omni Storm Lord, Variable Cord had stolen Tasuku's Neo Deck Case but was eventually recovered.|
|Bal's Future Buddy||Sun Belt|
Omni Lord Emblems
Other than having the same uses as other Core Gadgets, these Emblems (in the shape of an orb) are another way to recognise a being as one of the 8 current Omni Lords (Other than the amount of "horns" they may have).
When a current Omni Lord has reached the end of their life or seeks to retire, they may pass it down to another monster, an example being a disciple of theirs, allowing the new wielder to become the Omni Lord related to that Emblem.
It would seem that these orbs have a unique method of activation as despite being granted Tenbu's Emblem, Drum was unable to utilise it at first.
In H Episode 32, Count Dawn noted that the Emblems cannot be wielded by monsters of other worlds besides the world the Emblem's Omni Lord belongs to. This was the reason Mukuro Shigamine can never become its master even if he took possession of one from an Omni Lord.
|First Omni Beast Lord, Ziun||Green Orb||"Beast" Kanji|
|Second Omni Demon Lord, Asmodai||Turquoise Orb||"Demon" Kanji|
|Third Omni Water Lord, Miserea||Brown Orb||
Unlike the other emblems, the orb does not match world's colour (white)
Turns into a snowflake when luminized
|Fourth Omni Fire Lord, Burn Nova||Grey Orb||Given to be held by Ricky
|Fifth Omni Dragon Lord, Tenbu|
Drum Bunker Dragon
Passed down to Drum before Tenbu was devoured by Yamigedo. Later returned to Tenbu after Yamigedo was defeated. " Dragon" Kanji
|Sixth Omni Storm Lord, Variable Cord||Blue Orb||"Storm" Kanji|
|Seventh Omni Earth Lord, Count Dawn||Yellow Orb||
It can transform into a parasol to protect Dawn from the Sun's rays during the daytime.
|Eighth Omni Deity Lord, Grangadez||Orange/Saffron Orb||
Attached to his Chest
|Ninth Omni Brave Lord, Captain Answer|
Ninth Omni Brave Lord, Mukuro
Inside his body