Gabiru began as prince of the Lizardman tribe in the Great Jura Forest, notorious for his arrogance and overconfidence. As Chief Abiru's son and the tribe's first-named warrior, his natural leadership inspired loyalty among followers, though his inflated ego left him vulnerable to manipulation. Exploiting his ambition during the Orc Lord crisis, outside forces convinced him to rebel against his father, believing only he could save the Lizardmen. This act endangered his people, resulting in his banishment for treason; he accepted the punishment gracefully to shield his men.

Exiled with his loyal followers and younger sister Souka, Gabiru found sanctuary within Rimuru Tempest's Jura-Tempest Federation. Rimuru granted them a second chance, integrating them into the multi-racial society. This clemency sparked Gabiru's transformation. Receiving a new name from Rimuru evolved him and his followers into Dragonewts, gaining dragon-like wings, purple scales, larger horns, and enhanced physical capabilities. This allowed aerial combat and the ability to conceal wings for a humanoid appearance. Gabiru later underwent a further awakening, becoming a True Dragonewt and ascending to the title "Heavenly Dragon King."

These experiences reshaped Gabiru's personality. While retaining energy and enthusiasm, his arrogance transformed into humility and dedication. He developed fierce loyalty to Rimuru, embraced teamwork, and acknowledged past failures. Despite occasional comedic lapses like forgetting his wings mid-fall, he showed earnest commitment to self-improvement and protecting others. His relationship with Souka matured into a supportive sibling dynamic, with her often overseeing his actions. He also formed a collaborative partnership with Vesta, developing hippokute herbs and healing potions for Tempest's research.

Gabiru's combat abilities grew substantially. Originally a capable commander with tactical awareness, his evolution granted enhanced physical prowess and unique skills. He wielded the signature Vortex Spear and possessed the Unique Skill "Showoff," allowing limited destiny manipulation once daily. As a True Dragonewt, he gained the Ultimate Gift "King of Moods," enhancing cognitive speed, fate control, spatial manipulation, and multi-layered barriers. His power level placed him among Tempest's elite forces.

Within the Federation, Gabiru rose to leadership as commander of the Flying Dragon Corps, overseeing aerial defenses with wyvern units. He earned recognition as one of Rimuru's Twelve Guardian Lords, symbolizing his integration into the nation's military and governance. His journey from exiled prince to trusted leader underscored themes of redemption and adaptability.