Gaelion/Chronology

Volume 12
Gaelion's egg was gifted to Naofumi anonymously, along with a large amount of weapons and armor, it was speculated that it was either from Siltvelt or Shieldfreeden that gifted him the dragon egg. The decision was made for Naofumi to raise the egg and as such over the next few days is cared for by Naofumi up until it hatches at which point in time he assigns his slave Wyndia and new personal alchemist Rat to care for the infantile dragon.

The dragon spent several days playing pranks on Naofumi hoping to get his attention until he allowed the dragon to stay in his room with him, at which point in time the dragon ate the demon dragon core from Naofumi's armor and the Dragon Dragon's personality took possession of the young dragon's body.

Once the Old Gaelion took control of the child's body, it escaped back to its old nest. Naofumi and company decided to follow him, as both Filo and Naofumi started suffering consequences, due to pieces of the dragon core existing on Filo's body and inside the shield. Upon reaching the nest, close by the Eastern Village that once was plagued by the rotting body of the Old Gaelion.

They encounter Gaelion, now having changed into a "Wrath Dragon," due being linked to Naofumi's Shield of Wrath through the core piece inside the shield, sapping power from it.

After regaining his senses, thanks to Wyndia's intervention, Old Gaelion ends up being superseded by the Demon Dragon Core portion that was part of the composite core. During the fight, the body of the child Gaelion is expelled from the Wrath Dragon's body, with the core from the Demon Dragon becoming separated from the core of Old Gaelion.

Once the fight with the Demon Dragon has concluded, Old Gaelion called for Naofumi, presenting himself as "The Weakest of the Dragon Emperors," and proceeds to apologize for the entire problem brought up by both himself and the Demon Dragon. He then asks Naofumi two favors, to keep looking for Wyndia, and to not reveal to her daughter that he is kind of alive, despite her having finally accepted his death.

Finally, Old Gaelion promises to help Naofumi whilst he raises child Gaelion and his personality eventually merges with the child dragon's.

Volume 13
On the boat ride to Q'ten Lo, Gaelion and a few others were forcibly summoned by the Water Dragon into its cave. From there, it gives Gaelion a dragon emperor fragment which increases his stats and water-type resistances. Through Gaelion, the Water Dragon asks Naofumi and the others for help and then provides disguises for the group.

Entering Q'ten Lo, Gaelion turns out to be the only one legally able to kill monsters since he is a monster himself and a Vassal of the Water Dragon. With the power given to him by the Water Dragon, he was also able to power-down the stones buffing the enemies.

Volume 15
As Gaelion consumes dragon emperor fragment, he collects more dragon-related knowledge and powers. After returning from Q'ten Lo, Gaelion unlocked the dragon-related shields within the Legendary Shield which Fitoria had locked. He also decides to give the blessing to all the Heroes which allow them to use Way of the Dragon Vein magic. Finally, he conducts the class-up ceremony for all of the monsters. However, to his frustration, Raph-chan interferes with the ceremony to give a specific Raph-chan class-up.

Gaelion was also recruited to fight against the Phoenix birds Guardian Beast. He and Wyndia worked as partners during this fight.

Volume 16
After the fight with the Phoenix, Erhard's Master had finally removed the curse on the sword contained within the Orochi. Naofumi then fed it to Gaelion since it contained a dragon emperor fragment. Soon after, Gaelion joined the diplomatic party to Faubrey to learn about the Vassal Weapon wielders. However, it turned out to be an ambush by Takt. The group was only able to escape thanks to Raphtalia staying behind to cover their exit.

Later, when Takt started his campaign to take over the world in earnest Gaelion joined the group to directly confront him and his harem. Gaelion and Ren worked together to fight against the dragon emperor in Takt's ranks - Leludia - and defeated her. Gaelion then took the multiple dragon emperor fragments that she carried. At this point Gaelion believes that he possesses most of the dragon emperor fragments from his world and that he has the ability to unseal the Dragon King Guardian Beast. However, this would sacrifice himself which Naofumi would not allow.

Volume 17
From the information given from the dragon emperor fragments, Gaelion learned how to conduct the level-100 limit break ceremony. He then conducted it on everyone within Naofumi's village and party who could use it.

Volume 18
When the heroes decided to revive the Demon Dragon Emperor, Gaelion did his best to interfere and "overwrite" its personality during the ceremony. However, the demon dragon was able to revive with its personality intact.