Enki, also known by his Japanese name Rokuta, is the kirin of the kingdom of En. As a taika, he was born from a kirin fruit on Mount Hou but was transported to Japan, known in the Twelve Kingdoms as Hourai, during a storm to be born to human parents. His birth in Japan occurred during a period of intense civil war, and he was abandoned by his parents as a young child when they could no longer feed him. He was found starving and near death by his nyokai, a protective spirit, and returned to Mount Hou to be raised as a sacred beast.

Because he matured at a younger age than most of his kind, Enki's human form appears as a young boy, typically around early adolescence, despite being several centuries old. He has a bright, golden-haired appearance with violet eyes, and pointed ears that he often conceals with a cap when traveling in disguise. In his true kirin form, he resembles a graceful, golden-furred creature with a single horn on his forehead, a creature of great beauty that resembles a cross between a deer and a small horse.

Enki's personality is shaped profoundly by his traumatic origins. Having witnessed the suffering and chaos caused by war as a child, he developed a strong aversion to kings and rulers, whom he saw as warmongers responsible for the destruction of countries. Initially, he was deeply reluctant to choose a king for En, believing no human could rule a kingdom properly. This cynicism masks a fundamentally compassionate nature; as a kirin, he is inherently driven by justice and mercy, and he genuinely cares for the well-being of the common people. Despite his age and wisdom, he can be blunt, rebellious, and argumentative, often displaying a bratty and informal demeanor, especially when comfortable. He has a good sense of humor but is also known for being headstrong and taking risks.

The central motivation that drives Enki is the desire for a just and peaceful kingdom, free from the cruelty of inept or violent rulers. A pivotal moment in his past occurred when a desperate woman begged him to choose a king, explaining that people were starving and abandoning their children, just as he had been. Her words moved him deeply, prompting him to invoke a meishoku, a supernatural storm that allows passage between worlds, and return to Japan. There, he met Naotaka Komatsu, a man who would eventually prove himself a worthy ruler. Even then, Enki was initially hesitant, but he could not leave Naotaka's side and eventually recognized him as the true king, bringing him back to the Twelve Kingdoms. Naotaka ascended the throne as King Shoryu, and their trust was cemented when Shoryu successfully suppressed a rebellion in En.

Enki's role in the story extends beyond his own kingdom. He and King Shoryu are among the first to lend aid to Youko Nakajima, the newly chosen queen of the neighboring kingdom of Kei. Enki travels through the provinces of Kei with the half-beast scholar Rakushun, using his diplomatic skills to persuade local governors to abandon the false queen and pledge loyalty to Youko. He also plays a significant role in helping Taiki, the young kirin of Tai who is also a taika from Japan. Understanding the unique struggles of being born on Earth, Enki acts as a mentor and guide, helping Taiki come to terms with his identity and destiny as a kirin.

His most important relationship is with his king, Shoryu. Unlike the formal and distant relationships typical between other kings and their kirin, Enki and Shoryu share an easy, casual, and mutually respectful bond. They freely tease one another, and their interaction is built on a foundation of deep trust that has been tested and proven over centuries. This relationship represents a significant development for Enki, who was once a cynical anarchist at heart but learned to place his faith in a single worthy human. He also has a protective bond with Taiki, seeing in the young kirin a reflection of his own past struggles.

As a kirin, Enki possesses several notable abilities, though he himself claims they are not particularly outstanding. He can assume a human form and is functionally immortal, though he can be killed by severe physical trauma like decapitation. In his kirin form, he is able to fly. He has the power to understand any language, including the unspoken intentions of those who cannot speak, and to communicate with animals. He can subdue and form pacts with youma, or monsters, who then become his shirei and serve as his protectors, since he is a pacifist incapable of violence. His contracted spirits include a wolf-like rikaku named Haku Yokuhi. Enki is critically vulnerable to blood; the sight or even the smell of it can make him violently ill, and sufficient exposure could prove fatal. This sensitivity extends to violence itself, which causes him great distress. His powers can be sealed if his horn is bound, rendering him helpless. He can travel between the Twelve Kingdoms and Japan by creating a meishoku, a skill he uses periodically to wander the modern world.