Climb is a young man who serves as the personal bodyguard and loyal attendant to Princess Renner Theiere Chardelon Ryle Vaiself of the Re-Estize Kingdom. His past is one of considerable hardship; during his childhood, his parents vanished for unknown reasons, leaving him to live as a homeless street urchin. He survived by scavenging for scraps of food in the streets, often close to death, until he was discovered and taken in by Princess Renner, to whom he owes his life.

Climb's personality is defined by his unwavering dedication and intense work ethic. He is described as kind-hearted, hot-blooded, and determined, possessing a fierce resolve to protect the princess who saved him. This loyalty is absolute, and he is willing to sacrifice his life for her without hesitation. He trains tirelessly every day to improve his swordsmanship, seeing his service to Renner as a way to repay the debt he owes her. However, this singular focus and the preferential treatment he receives from the princess have left him with few close relationships outside of his duty to her. A key aspect of his character is his complete unawareness of Princess Renner's true, darker personality, as he is easily fooled by the benevolent facade she presents to the public. Despite being told by others, including the warrior Gazef Stronoff, that he has no natural talent for combat, Climb's determination drives him to seek any path to greater strength.

Climb's primary motivation is singular and clear: to become strong enough to protect Princess Renner, who is his entire world. He is acutely aware of his own limitations, as he has no special inborn talent for swordsmanship or magic, and has self-evaluated his abilities to be roughly equivalent to that of a gold-rank adventurer. This perceived inadequacy pushes him to seek out powerful mentors. His role in the story becomes prominent during the conflict with the criminal syndicate Eight Fingers. He is loaned by Princess Renner to the adventurer group Blue Rose to assist in their operations against the organization. Later, he encounters Sebas Tian, the butler of Nazarick, after witnessing him save a child from a bully. Deeply impressed by Sebas's skill, Climb begs him for training, a request Sebas grants after assessing his character. During this training, Sebas warns Climb that the technique he wishes to teach could be fatal if he has no one precious to protect, to which Climb responds with the thought of Princess Renner. He also forms a partnership with the veteran warrior Brain Unglaus, and together with Sebas, they raid an Eight Fingers brothel to rescue a woman named Tuareninya Veyron. In these battles, he demonstrates not only his courage but also a cleverness that helps him overcome a foe named Succulent, an illusion magic user.

Climb's development is less about becoming overwhelmingly powerful and more about confronting the hard limits of his natural abilities. The narrative establishes that he has largely reached a ceiling in his growth as a warrior, a fact he struggles against but refuses to accept as a barrier to fulfilling his duty. His journey is one of perseverance; he learns to leverage his determination and resourcefulness, such as using magical items provided by the princess to deal with traps and secret doors, rather than relying on raw talent. He also gains valuable combat experience and allies during the fight against the Eight Fingers.

In terms of abilities, Climb is a competent but unexceptional swordsman whose power is derived from relentless effort rather than innate genius. He wears a distinctive set of pure white full plate armor given to him by Princess Renner and fights with a broadsword and shield. Because he cannot use magic on his own, he relies on magical items to supplement his abilities, including a ring created through wild magic that is said to push a user's abilities to their absolute limits. While he can hold his own against ordinary opponents, he is vastly outclassed by the supernatural beings and top-tier warriors of the world.