It's a funny story actually!
People from my hometown are nicknamed as 'burnt'. A few years ago, I also played a lot of Elsword, and I mained a character called Raven.

One day I made an account to get to high level stuff, so I took those two ideas, made it english, and I landed on BurnCrow. The SP is a terminology from MegaMan Battle Network & StarForce games, used to indicate the highest level version of a specific boss.

I was making a high level account, so BurnCrowSP was fitting. I began using that name for mostly everything, and it just stuck!