Ikaros loves petting round things, especially watermelons, she even has a farm full of them. Even when Tomoki tried to take a watermelon from her to consume it, she refused to give it up and kept it for herself.
She begins the series with a poor grasp of human emotion, but after Nymph tries to unlock her memory to make her realize she isn’t a “Pet-Class Angeloid”. Ikaros’ memories on “Self-Repair” is also unlocked and she quickly unlocks the rest of the restraints put upon her, making her weapons and emotions effective.
As the story progresses it becomes clear that Ikaros is not merely a “Pet-Class” Angeloid, she is actually a “Battle-Class” Angeloid. After she realises that she is a “killing machine”, she tries to keep it a secret from her master Tomoki. She is barely hurt when she is shot, she is capable of flying at Mach 24, and is able to withstand pressure way better than most submarines. In the past, she was called the “Queen of the Skies” and “Uranus Queen”, and responsible for throwing Synapse into disorder after she was ordered to by a human due to Mikako causing her to malfunction. She was originally sent to Earth as a weapon of judgment and was responsible for destroying The Tower of Babel.
As the series progresses, Ikaros begins to develop her feelings for Tomoki. However, since she is lacking in her emotional aspect, it takes time for her to realize her feelings. Later on, she misunderstands Tomoki’s actions and perceives him to be proposing to her during one of Mikako’s planned activities and asks the others about it.
When she thinks of Tomoki, Ikaros feels a “pain in her reactor”. At the end of the eleventh episode when the pain reaches its peak she shuts down, and reboots. When she awakens Nymph discovers she was on the verge of losing her memories.
At the end of episode 9 of 1st season, Ikaros kisses Tomoki.
At the end of 2nd season of Sora no Otoshimono, after mistaking Tomoki’s saying “We’ll be together forever.” as a proposal, she almost gets married with Tomoki, after telling Mikako.