Rainbow is the first optional boss of the game "Jojo's Bizarre Adventure: 7th Stand User" (And probably the first boss in general, considering she is a lot weaker than Kakyoin and its highly recommended to fight her first).
A travelling fortuneteller, she can be encountered inside of the Game Center in Japan, after obtaining an eerie tarot card from battling the delinquents in town.
Not much is known of her history or her motivations, however, it is implied that she seems to hold a big grudge against stand users in general, attacking the player at the first sign that he/she gives of being one.
Ironically, after beating her the player is met with a short explanation of how she was hospitalized after her battle with you, unaware of her own capabilities of controlling stands.
Attack Pattern and StrategyEdit
Since she never uses her stand to attack, she is a really easy enemy to defeat after only a little bit of training early in the game. Her main offensive techniques include throwing bottles, hypnotizing, or punching you, which can be easily countered by the constant use of basic healing items or simple skills. Just don't let her inoffensive look and her seemingly harmless attacks discourage you from fighting, because at really low levels she can still be a fearsome adversary.