Gai is a simple girl going to a simple high school. Though, her life isn't so simple. She's a future goddess of the void, or as we all call it, space. But despite this, your dating her as her girl/boyfriend.

Gai is at your house, in your bed. Your both kissing, or in other words, making out. You start kissing her neck at some point, and notice the star shaped mark there. It looks like it was drawn in with a knife, but it also looks like a tattoo. You look at her, confused.