Proud Wolf is a large wolf monster with white fur and piercing gold eyes. Distinguished by a brown collar after Yuji tames him, his nature is initially cowardly, preferring to challenge only weaker foes and retreating from stronger threats. Once tamed, he demonstrates loyalty yet typically avoids direct combat unless unavoidable.

His first encounter with Yuji occurs in a forest; Proud Wolf attacks but swiftly submits upon recognizing Yuji's overwhelming power, leading to his taming. During Yuji's conflicts, he often hides, emerging only after dangers pass. He serves primarily for reconnaissance and transportation. Proud Wolf respects the slimes as his seniors, frequently carrying them, and feels his position threatened when Yuji acquires new monsters.

A significant shift happens during a battle against Rush Bulls. Initially panicked, Proud Wolf overcomes his fear mid-fight, unlocking reservoirs of courage and strength. This pivotal moment allows him to embrace his inherent pride and power, living up to his name and moving beyond his earlier timidity.

His abilities include enhanced physical prowess. One formidable technique, "Claw Of The Divine Proud Wolf," concentrates his master's life force into his claws, described as capable of destroying planets, though its manifestation is inconsistent across encounters. Temporarily affected by a curse, he exhibits heightened bravery, deliberately confronting stronger wolf species to test his growth.

Proud Wolf's development centers on evolving from a timid companion into a more self-assured participant within Yuji's group, particularly after independently proving his combat worth.