Astrea, a First Generation Angeloid designated Type Delta, specializes exclusively in close combat. Deployed by the Master of Synapse during the Forte Arc, her mission targets Tomoki Sakurai and the retrieval of rogue Angeloids Ikaros and Nymph. Her combat capabilities exceed Ikaros' in specific areas, enabled by Acceleration-Type Wings granting hyper-speed mobility and two specialized weapons: the Super Vibrating Photon Blade "Chrysaor," capable of slicing through Ikaros' Aegis shield, and the "Aegis-L" shield, offering superior frontal defense at the cost of covering only half the angular area and leaving her vulnerable to flanking attacks. This singular focus renders her extremely disadvantaged against long-range opponents. Physically, Astrea stands 159 cm tall, weighs 48 kg, and has measurements of 91-56-86 cm, making her the character with the largest bust size in the series. She possesses long golden-blonde hair reaching her ankles, red eyes, and wears blue attire similar to Ikaros', complemented by white and blue wings. Her personality stems from low intellectual processing capacity, a deliberate omission to prioritize combat prowess and emotional capacity, leading to frequent descriptions as an "idiot" or "airhead." This manifests as poor coordination and naive actions, like forgetting to catch herself when tripping or attempting to obtain nutrients by burying herself in the ground. Despite this, she exhibits strong emotional intelligence and demonstrates practical common sense in situations where other Angeloids falter. She experiences intense emotions, including deep loyalty and affection. Her development centers on forming profound emotional bonds. Ordered to kill Nymph during the Chaos Arc, she hesitates due to Tomoki's urging to follow her own desires, leading her to sever her chain to the Master of Synapse and break her contract. Protecting Tomoki and allies, she engages Chaos, a Second Generation Angeloid she later views as a younger sister. Her emotional investment fuels her combat here, though Chaos exploits her long-range weakness. She later rescues a drowning Ikaros post-battle, showcasing growing protective instincts. Her relationship with Tomoki evolves from antagonism to unofficial loyalty, though Mikako Satsukitane later becomes her official master. She develops romantic feelings for Tomoki and participates in his daily misadventures, often falling victim to his perverted schemes. A sibling-like rivalry forms with Nymph, frequently clashing over minor issues like food. Her bond with Chaos becomes a recurring emotional anchor, motivating actions in subsequent arcs like the Return of Chaos and Melan Arcs. In the final storylines, her wings—initially destroyed in battles—regrow spontaneously during a moment of shared happiness with the other Angeloids. This regeneration symbolizes her emotional fulfillment and permanent integration into Tomoki’s life, solidifying her transition from weapon to compassionate individual.