For the eighth Knight Gundam work, the series is taken to the alternate world of Llion Cardzi. The series had included simpler designs for characters and a new format for the cards, which included details about the world. The Carddass series was cancelled after Chapter 2 due to stagnant sales, but the manga finished the series. The remaining story was not told until SD Gundam Ultimate Battle. In the world of Llion Cardzi, classes can be changed using specific stones known as Rune Shards. This becomes a key part of the plot. The series uses designs from After War Gundam X and Mobile Suit Gundam: The 08th MS Team.
The story focuses on X, who goes on a journey to fulfil his dream of becoming a knight by mastering the classes of swordsman, warrior, and mage. However, he is suddenly thrown into battle against the Demon King Army.
- The Swordsman of Llion
Swordsman X travels to the outside world in order to become a knight. On his journey, he finds out about the Demon Beast Patulia and joins the Paturia military's mercenary force.
- The Strongest Warrior
Swordsman X changes to a Warrior using the Rune Shard from defeating Patulia. To master his ability as a warrior, he enters a fighting tournament in Olvania, however, the event is swirling with controversy around Giant Ashtron.
- The Path to a Mage
After the fight against Ashtron, Warrior X changes to a Mage using Princess Tiffa's Rune Shard. Mage X travels to free the Coulomb Kingdom from Dark Mage Virsago.
- Final Quest
After Magic Monster Chest Break is defeated, the Coulomb Kingdom is released and Mage X is given a Rune Shard to transform into Knight X, and becomes the knight of hope as well. Knight X travels to fight the final battle against Great Demon King Zaidaria.
Fencer X/Warrior X/Mage X/Knight X/Hero X
A young man whose bloodline is of the Satellite Clan. Immeditatly after starting his journey to become a knight, he is thrown into the battle against the Demon King Army, which has been causing chaos within the Llion Cardzi world. He can use Rune Shards to change his class.
- Design Basis: RX-79［G］Ez-8 Gundam Ez8 (Armor)
The sole survivor of Kojima Village, which had been destroyed by Demon Patulia. After his village's destruction, he pursued the monster in anger before finding out he can't harm it during the day from X. Despite looking like a member of the Gundam clan, he is actually a GM wearing a Gundam mask. He changes classes by changing disguises, except he doesn't get the extra strength Rune Shards give.
A mercenary hired by Lady Maria. He is actually a knight from the Coulomb Kingdom. He had trained in the country and ultimately developed the Godspeed Sword Technique. He can shred enemies as he dances around the battlefield.
A mercenary hired by Lady Maria. He is actually a knight from the Coulomb Kingdom. He is calm and uses tactics to attack enemies with his spear at close range.
Dog Freeden/Guardian Dragon G-Falcon
X's dog. Its true identity is the Guardian Dragon G-Falcon, who was turned into a dog by Sorcerer Virsago's magic. In the final battle, it used the job change spell to change X from a Knight to a Hero and sacrificed its life to turn into the Brave Armor.
- Design Basis: Techcs Farzenberg
The guardian of the Job Change temple. He was once a prophet from the Satellite Clan, but became a priest of the job change temple. He guided X to become a knight using various rituals. In the manga version, he lived with X and hid his true identity under the guise of being the captain of the guards. He was later killed in an attack on the Job Change temple by Zaidaria, but engraved the job change spell into his cane so X could turn into a knight.
The lord of Kalen Providence. A ruler trusted by the people for her kindness. When Demon Beast Patulia appeared, she hired mercenaries and two knights to use as a trump card.
- Design Basis: Tiffa Adill
The daughter of Maria and granddaughter of King Of Heart. She was kidnapped by Ashtron while studying in Adel and was made the grand prize for the Olbania Fighting Tournament. Her pendant is imbedded with a magic Runeshard. She later traveled with X to the Coulomb Kingdom. She was turned into a rat by Virsago's magic, but helped X in battle. After Virsago was defeated, she returned to her normal form.
King of Heart
The king of the Coulomb Kingdom, one of the most powerful kingdoms in the world. The father of Lady Maria and grandfather of Princess Tiffa. He sent out two knights upon finding out Tiffa was in danger, he sent out two knights to help her. He fought in the past. He was turned into a frog due to Virsago's magic, but returned to normal after he was defeated.
X's father. He lost his life in the past fight against Zaidaria.
A jelly-like monster that does not have a permanent shape. Its main tactic appears to be attaching to the face of others and cutting off their breathing by covering their nose and mouth. There seems to be several kinds.
A monster that eats lava and can quickly burn down a forest with a single breath.
Golem The O
A stone statue made to protect an ancient king. It began to move in order to recover treasure stolen by robbers.
A flying monster. The feathers from its wings can tear through armor.
Demon King Zaidaria
The Demon King that suddenly invaded Llion Cardzi. In the final battle, it combined with the Octopus Dragon and broke down to only a brain due to Knight X's attack. It seems to be able to change form. After being defeated by X, it vanished in a ray of light.