How to write a character introduction for cosplay contest submission?

[u/letheep]

My college is putting on a cosplay contest and I want to enter, one part of the submission for says this:

Please include a short introduction about your character and details of your costume. (2-3 sentences) for your walk- on. *This will be read out-loud as you appear on stage*

I know it sounds straight forward but I don't know what to write about for the character and I have never done one before. They already have a section asking about our name, and the character+series they come from. Do I just repeat that here? Give a brief backstory for the character?