Kumayuru is a summoned beast who appears as a black bear and serves as a loyal companion to the protagonist Yuna. Together with the white bear Kumakyuu, Kumayuru forms one half of a pair that Yuna can call upon at will. The creature possesses high intelligence, comprehending human language without being able to speak, and expresses itself through actions, body language, and subtle facial cues. Its eyes are described as slightly slanted, which gives it a distinct appearance compared to its counterpart.

Kumayuru can change size between a compact, stuffed-animal form suitable for being carried or held, and a normal adult bear size large enough to carry several people on its back. In larger form, Kumayuru serves as Yuna’s primary means of transport across the land, and it generates a protective energy that wraps around its body, shielding riders from wind pressure and preventing accidental falls. This makes Kumayuru a reliable and secure mount even at high speeds or in rough terrain.

Originally possessing considerable physical strength, speed, and toughness, Kumayuru’s capabilities were further enhanced when Yuna equipped it with a special spirit stone called Kumamonite. With this enhancement, the bear became faster, stronger, more durable, and gained the ability to perform magic, greatly augmenting Yuna’s tactical options in battle. Offensively, Kumayuru uses its natural bear might alongside charged energy attacks, and it can intimidate bandits or monsters simply through its imposing presence. Beyond combat and transport, the bear has a keen sensory ability: it can detect the presence of people and monsters over distance and even locate areas where medicinal herbs grow, assisting Yuna in gathering and exploration.

Kumayuru’s personality shows a gentle and devoted nature toward Yuna, but it also exhibits a hint of possessiveness. If Yuna appears to favor Kumakyuu, Kumayuru may become visibly sulky, requiring the master to maintain a careful balance in her attention. This emotional responsiveness underscores a deep bond between Kumayuru and Yuna, shaped by the many adventures they share. Throughout the story, the bear remains a constant, protective presence, acting as guardian, mount, and steadfast ally. Although Kumayuru’s core nature does not undergo dramatic change, its relationship with Yuna matures in mutual trust, and its abilities evolve through the power of the Kumamonite, enabling it to face progressively more dangerous threats. In this way, Kumayuru serves as both a symbol of Yuna’s strength and a foundational support that enables her to protect those around her.