Well, you can have your star runner be any kirby creature you want; even make your own species for this (as long as it looks like it could belong in the kirby universe), albeit each one has to follow several guidelines; mostly from
Star Warrior Class - Star Runners [OPEN] ^v^ there's also a cool little guideline for an old contest that helps flesh out your character right here
[CONTEST] STAR RUNNERS [OPEN] [READ THROUGH] if you have any questions, do let me know!