Ikaros

The title character (she is "Heaven's Lost Property") and main heroine of the series, Ikaros is a beautiful gynoid known as an "Angeloid". She falls from the sky at the beginning of the story. After Tomoki recovers her, she forms a bond with him and calls him master: the imprinting is symbolized by a chain from her collar to his hand. She has an expressionless face that makes the other characters wonder if she will ever smile. Her emotions develop slowly, due to her programmed setting of high battle abilities and high processing abilities but low emotional abilities. Despite this, she develops genuine feelings of love for Tomoki.

Spoiler

She also goes along with any of his perverted schemes, and eventually burns up into nothing after carrying Tomoki to Synapse, showing him her smile for the first time.She and the others are later resurrected by Tomoki's final wish.

Although she initially states she is a "Pet-Class" (entertainment-purposed) Angeloid, she is actually a "Strategic Battle-Class" Angeloid. Her name comes from the Greek mythological character Icarus, a craftsman's son who flew too close to the sun and fell from the sky.