Ryujinmaru originates as the Gold Dragon, one of the Shinbu Dragon Gods from the divine realm of Shinbukai. This golden-scaled mythological Chinese dragon serves as the true spiritual essence within the character. Merging with a clay figure sculpted by Wataru Ikusabe in the primary continuity transforms Ryujinmaru into a sentient combat mecha, becoming Wataru's primary partner. Within the cockpit interface, Wataru pilots from the dragon's head position amidst a cosmic space.

Across different continuities, Ryujinmaru's origin adapts while retaining core divine elements. In *Mashin Creator Wataru*, the Gold Dragon merges with Wataru Hoshibe's cubic creation, similarly emerging as a sentient partner. This version features design asymmetries, including a dragon head on its right shoulder and a detachable backpack unit functioning as both shield and bowgun. It is identified as one of the God 7 deities of Chubukai. The *Super Mashin Hero Wataru* timeline introduces Ancient Ryujinmaru, an ancient titan and legendary hero who protected Mount Soukai before his essence was later housed in a mecha form.

Ryujinmaru's personality consistently emphasizes candid and concise communication, primarily offering tactical advice during battles. The character shares a profound spiritual bond with Wataru across all iterations, described as connecting "heart to heart" through the dragon's horns. This bond culminates in narrative arcs where mutual recognition of conscience activates Ryujinmaru's true power, as when Ancient Ryujinmaru acknowledges Wataru's heart as "the true sword to slay evil."

Combat capabilities evolve significantly. The primary arsenal includes close-range techniques like Dragon Fang Fist (龍牙拳, Ryugaken) and Flame Dragon Fist (炎龍拳, Enryuken). Signature finishing moves involve the Soaring Dragon Sword (登龍剣, Toryuken), which adapts elemental variants such as the life-draining Blazing Dragon Sword (火炎登龍剣, Kaen Toryuken) and the ice-based Frigid Dragon Sword (極寒登龍剣, Gokukan Toryuken). The *Mashin Creator Wataru* iteration introduces ranged combat with Dragon Arrow (龍の弓, Ryuu no ya), utilizing the bowgun form of its backpack unit.

The *Seven Spirits of Ryujinmaru* anniversary project expands the character into multiple parallel world variants, including Genryumaru, Ryugekimaru, and Seiyuumaru. Specific details about these forms require supplementary media like novels or manga for full context. Ryujinmaru's resilience is demonstrated through temporary destruction, such as after using the life-force-depleting Blazing Dragon Sword, requiring resurrection via yin-yang orb.