It's Galaxi-chan!

Originally designed by @HrusaArt for GalaxiFEST 2020, she has stuck around for every year of GalaxiFEST since then. She gets new artwork from the same artist to grace the event every year, usually with a new costume - you can even see her in chibi form as of recent years!

The artwork shown here is the illustration drawn and used for GalaxiFEST 2022.

We don't know too much about her origins or personal life, but we can tell you:

Her anniversary is August 18th - on that day in 2020, her design was first shown to the public on promotional graphics for the first GalaxiFEST
Her Western Zodiac sign is assumed to be Leo
Similarly, her Chinese Zodiac sign is presumably the Rat
She's old enough to drink in most countries
Her favorite color is blue - her original outfit in 2020 was primarily blue, but has since started wearing pink because it "pops" more against her blue hair
She likes glossy fabrics because of the way they shine under club lights
She is said to have a Canadian accent, despite nobody knowing where she actually hails from
She considers Noc-tan (the Nocturne Rave mascot) one of her besties - the friendship isn't entirely mutual
She claims to be "not too bad" of a DJ herself
She dreams of owning her own space station someday