Kinjo is the young leader of the Kunie clan, a powerful and ancient organization that controls the fundamental infrastructure of Akiba, including its banking systems, delivery services, market operations, and the city guard. As a member of the Half-Alv race, he has a youthful appearance with black hair and deep purple eyes, often dressed in a high-collared tuxedo that gives him a formal and somewhat anachronistic air. Despite his young-looking face, observers have noted that his hands bear the marks of a middle-aged man, leading to questions about his true age and the nature of his existence. In fact, although referred to as a single individual, there is evidence to suggest that multiple beings share the name Kinjo, all possessing the same memories and knowledge, making it difficult to distinguish between them.

His personality is defined by an almost impenetrable calm and a stoic demeanor that makes it hard to tell if he is constantly wearing a poker face or if he genuinely has difficulty expressing emotion. He is known for his exceptional skill in dialogue and negotiation, always remaining polite but unwavering in his position, even when dealing with formidable strategists like Shiroe. Kinjo prefers to resolve matters with words rather than through combat and approaches every situation with cold, unshakable logic, rarely revealing his true feelings or intentions. On the rare occasions when he does show excitement, such as during the unveiling of a new prototype device, it stands out as a notable deviation from his typical emotional flatness.

His background is deeply intertwined with the history of Elder Tale itself, as he originally served as the model for the non-player character bankers within the game, possessing a special uniform and appearance tied to that role. After the adventurers became trapped in the game world, his responsibilities expanded dramatically. He holds the title of Successor, a unique, non-playable class whose full combat capabilities remain unknown but are speculated to involve the use of various devices in battle. Kinjo is driven by the administration and preservation of Akiba's systems, serving as a neutral party who manages the city's magic boundary, the guard system, and later the crucial urban teleportation network. His primary motivation appears to be the careful stewardship of the Kunie clan's immense resources, particularly the legendary gold, which is said to bring both a blessing and a curse, a treasure that is no treasure at all.

Kinjo's role in the story is primarily defined by his interactions with Shiroe, the master strategist of the Round Table Alliance. Their most significant encounter occurs during the Gold of the Kunie arc, where Shiroe invites him to a secret negotiation in a snowy, rural area. The talks ultimately fail because neither side is willing to reveal all their information, though Kinjo provides a cryptic hint about the location of the Kunie clan's base of operations. This tense relationship continues when Shiroe delves into the depths of the Abyssal Shaft dungeon, where he finds Kinjo waiting alongside a massive vortex of gold and the raid boss known as Uru of the Nine Prison. In this high-stakes meeting, Shiroe successfully negotiates for temporary access to the Kunie gold, allowing him to purchase all the important structures and open fields on the Yamato server and transfer ownership back to the server itself. Kinjo also has a notable connection with Raynesia, informing her of a dangerous rogue member of the Kunie clan, a former Royal Guard named Enbart Nelles who stole a Mobile Armor suit. He reveals that stopping this rogue would require shutting down Akiba's defensive magic circle for a full ten years, a cost he ultimately accepts to pay.

Throughout the series, Kinjo undergoes subtle but significant development in his role within Akiba's political structure. After the collapse of the original Round Table Alliance, he remains helpful in managing the city's systems. Later, to reflect the growing presence of the People of the Earth in the city, Shiroe invites him to join the new Round Table Council as an advisor on urban management, a position he formally accepts following Raynesia's election victory. This marks his transition from a neutral, behind-the-scenes infrastructure manager to a more overt political stakeholder in the city's governance. His notable abilities include his extraordinary knowledge of the game's economic and logistical systems, refined by his background as the original banker model. He demonstrates keen awareness, such as instantly recognizing when a powerful raid boss has been defeated, confirming his deep connection to the world's underlying mechanics. At the deepest levels of the Abyssal Corridor, the being waiting for Shiroe alongside the ninth raid boss is not actually the true Kinjo but a nearly identical entity, created for game efficiency reasons, with only minor differences in clothing distinguishing them.