It's hard to say exactly what 'yandere grey visual novel' is about without more context. However, generally, in a yandere - themed visual novel, you're likely to encounter characters with unbalanced mental states when it comes to relationships. The 'grey' could suggest that the overall tone or the nature of the events in the story is not clear - cut. It could have elements of mystery, drama, and psychological exploration. There might be a focus on the character's internal struggles, especially the yandere character who may be torn between their loving and possessive sides.
A 'yandere grey visual novel' is likely to be a visual novel that involves yandere characters. Yandere characters are typically sweet and affectionate on the surface but can become extremely possessive and violent when it comes to love or protecting their loved ones. The 'grey' part might refer to a more complex or morally ambiguous aspect in the story. It could explore themes like love, obsession, and the darker sides of human nature through its narrative and character interactions.