D, whose true identity is the deity Wakaba Hiiro, masqueraded as an ordinary student while neglecting her divine duties. When a previous Hero and Demon Lord assassinated her entire class via explosion to target her, she reincarnated her classmates into another world. To avoid detection by other gods who might recall her to work, D fragmented her soul and memories into a classroom spider, creating the entity Kumoko (White). This deception simulated Wakaba Hiiro’s reincarnation and death.

As the "God of the End," D holds the highest rank among the System's Administrators. She designed this RPG-like System as a curse and solution after humanity nearly destroyed the planet, converting energy into skills for living beings; upon death, the energy returns to heal the world. D occasionally observes reincarnators like White but remains largely neutral.

D exhibits a self-centered, playful personality, prioritizing amusement above all. While claiming motives beyond entertainment, she sadistically manipulates others—like toying with White’s hardships. Her pettiness includes ensuring most reincarnated female classmates developed small breasts due to her own lack of endowment, reacting angrily to exceptions. She reincarnated a male classmate who asked her out into a female body, ironically freeing him to embrace his homosexuality.

Driven by grudges, D manipulated specific reincarnations—such as transforming Shinohara Mirei (Fei) into an Earth Dragon over past bullying rooted in jealousy of Wakaba’s popularity. Her influence extended to creating White’s companions (Ariel’s Puppet Taratects) and assigning roles to entities like Güliedistodiez, whom she ordered not to interfere with reincarnators despite his balance concerns.

In the story’s conclusion, D captures White to ensure eternal companionship. White laments this "bad ending," permanently separating her from Ariel and Sophia while binding her to D’s service.