Tsukuyomi

"God surely is kind, isn't he? He brought two people who never had a mother in the real sense... and a mother who gave birth to soulless children... together. Perhaps... there's more to that than meets the eye."

The Crow Girl is an unnamed minor yet pivotal character in the Oshi no Ko manga series. She is a seemingly supernatural being apparently aware of everything that transpires within the story.

Personality
The Crow Girl is an enigmatic being whose motivations and goals are shrouded in mystery. Befitting her appearance, she bears the overall demeanor of a creepy child, acting mischievous and almost always having a smile on her face.

When approaching others, she tends to tease them about their insecurities. However, should they ignore her, she will then try to get their attention by confronting them about their desires and offering vital knowledge to help them achieve their goals, though she teasingly keeps key information to herself.

Background
At some point following Ai Hoshino's death, the Crow Girl confronted Aqua. As he was holding out hope that she might perhaps have been reincarnated like himself and Ruby, she informed him that his mother's soul had left this world.

Private
The Crow Girl is first seen after Aqua tells Gorou Amamiya's backstory to Akane. Having seemingly overheard the conversation despite not even being in the same area, she mumbles to herself how "god must be kind to have brought him, Ruby, and Ai Hoshino together", though she also notes that there "might be more to it".

Movie
Around the same time the movie 15 Year Lie is green lit, the Crow Girl comes to see Aqua, asking him what he is thinking about, his sister, his ex, someone who loves him or even his mother. She repeats the fact that Ai was not reincarnated like he and his sister were and that he should be thinking about why he was reborn at all.

Trivia

 * A popular fan theory is that the Crow Girl is, in fact, the Japanese deity Yatagarasu.
 * Yatagarasu is known as the "eight-layered crow", similar to how the Crow Girl is constantly surrounded by eight crows.
 * Yatagarasu serves as a guide to those who the gods deem worthy, like how the Crow Girl guides Ruby onto her quest for revenge.