Ogaro is a first-rank angel titled the "Angel of Darkness." Sent to Earth with twelve other angels by the retiring God, her mission was to select a human candidate to become the next God. She chose Shuji Nakaumi, granting him her first-rank abilities: wings for flight and a red arrow that compels love and obedience for 33 days. She could not bestow the white arrow, reserved for special-rank angels.

Ogaro possessed unique knowledge of the celestial realm and God's true nature, information concealed even from other angels. She revealed to Shuji that God is not benevolent but a parasitic entity formed from human prayers, sustained by human belief and holding the power to annihilate humanity. Sharing this forbidden knowledge risked her demotion to second-rank, which would have stripped Shuji of one angelic tool.

After Shuji won the competition and became God, Ogaro ascended with him. In the new divine realm, she learned God's full role: observing humanity to decide its ultimate fate. The entity that appointed her explained its original intent to end humanity due to inherent suffering and flaws. Agreeing with this assessment, Ogaro, now acting as God, chose to execute the extinction plan. She committed suicide, triggering the erasure of all human life and fulfilling the entity's design.

Ogaro has white hair and violet eyes. Her title "Angel of Darkness" reflects her role in conveying bleak truths about existence and divinity. Her actions and revelations critically shaped the series' exploration of free will, despair, and the consequences of absolute power.