The Star vs the Forces of Evil fandom (or Star for short) is a small fandom surrounding the cartoon aired on Disney XD
SVTFOE has long brown hair held back with a devil horns headband. Her cheeks have rose-colored hearts on them. She wears a turquoise dress with a pink squid in the center, pink and orange striped stockings and rain boots. She occasionally wears a red hoodie over the dress and/or a yellow star-shaped bag. She is also in possession of a magic wand and Dimensional Scissors (used to cut portals into different dimensions).
She is a very hyperactive 14 year old girl who loves martial arts and claims to be a "misunderstood bad girl" (even though she is always extra cautious about things, all the fandoms she knows call her the "safe kid").
Both of the shows feature 14-year-old kids with magic powers, who both happen to be bubbly and cheerful a lot of the time. Both of the characters sometimes might get out of hand, but will always fight for what's right.
When Gravity Falls Fandom is in the mood, both of them do fun stuff together, like solve mysteries or play with cute animals. The characters in their shows share similarities in terms of personalities as well. For example, Dipper is similar to Marco, and Mabel is similar to Star.