Daedalus created the first-generation Angeloids: Ikaros, Nymph, Astraea, Chaos, and likely Oregano. She originates from Synapse, a realm where inhabitants evolved parallel to humans but achieved advanced technology over eons. To combat widespread unhappiness among Synapse residents, she invented the Rule, a wish-granting device. While the Rule initially brought contentment, it ultimately triggered an existential crisis, causing mass suicides that drastically reduced Synapse's population. In response, Daedalus participated in recreating the universe and creating humanity alongside Angeloids for amusement. Observing humans, she and other Synapse residents grew envious of their ability to dream. This led to the creation of a dome where they project their consciousness into artificial human bodies on Earth to experience dream lives.

Her own dream life began as Sohara Mitsuki, Tomoki Sakurai's childhood friend who died young from illness. After this dream death, humans forgot her existence, including Tomoki. To prevent him from forgetting entirely, she created a clone of her dream identity—the Sohara seen throughout the series—and sent it to Earth. Later, seeking help for Synapse's unresolved existential issues, she sent Ikaros to Tomoki, initiating the main events.

Daedalus exhibits a calm demeanor and profound care for her Angeloid creations, whom she considers daughters. She demonstrates exceptional intelligence as Synapse's top scientist, responsible for inventions like the Rule, and holds strong disdain for cruel individuals like her former research partner, Minos. Her interactions occur primarily through Tomoki's dreams, where she warns of dangers or requests aid, reflecting her protective nature and strategic approach to safeguarding both Angeloids and Synapse residents.

Physically, she resembles her clone Sohara, sharing height and facial features but differing in breast size. She possesses long blue hair and white wings (depicted with four wings in the manga versus two in the anime) and is typically barefoot. Due to implied frail health, she rarely walks or stands, often seated on a cloud-like floating vehicle.

Throughout the series, Daedalus appears in Tomoki's dreams, initially as a fleeting figure who leaves him distraught upon waking. Her role expands as she guides him to protect Angeloids and reveals Synapse-related threats, such as stronger Angeloids created by Minos. She covertly intervenes at critical moments, such as rescuing Eishirō Sugata from Minos's Harpies. Her most significant revelation occurs in the final arc, where she discloses her true identity as Tomoki's deceased childhood friend and her creation of the Sohara clone.

In the movie *Eternally My Master*, she monitors events from Synapse, expressing dismay when Tomoki breaks Ikaros's imprinting chain and relief when he restores it after understanding Ikaros's devotion. She acknowledges that her initial goal of sending Ikaros for Tomoki's aid evolved into a deeper bond between them, fulfilling her underlying wish for his happiness.

Her abilities center on high intellect and scientific innovation rather than combat. She demonstrates dream visitation, portal creation, and remote surveillance. She also wields influence within Synapse, enabling covert actions like Sugata's rescue. Her name derives from the Greek myth of Daedalus, father of Icarus, aligning with her role as creator of Angeloids like Ikaros.

Key relationships include viewing Angeloids as daughters, antagonism toward Minos, unresolved affection for Tomoki stemming from their shared past, and mentorship of Sugata during Synapse visits. Her creation of Sohara's clone underscores her desire to remain in Tomoki's life indirectly.