So you may be asking, who or what is Cirno?
Cirno is an ice fairy from Touhou, known for being childish yet a moron.
The following is probably the most popular Cirno fanmade content and at the very least you'll find the song catchy.
What makes her special(-ed)? For one she has one of the simplest safe-spots, where you can simply stand right in front of her and she won't be able to hit you.
We also have "I'm the strongest" even though she is potentially one of the weakest characters but at the very least the strongest or second strongest fairy after clownpiece.
Anyway, that's pretty much it. I'm sure we'll have some cute Cirno stuff in the comments afterwards which is what I'm looking forward to.