Koji's appearance is more or less identical to all the other generic Daku enemies on Sheo Beach and Sheo Islands. However, instead of wearing the mask, choker, and warmers like the competitors, Koji wears a normal unbuttoned sapling yellow shirt, a crystal pendant, and a pair of stylish sunglasses. The only article of clothing Koji shares with his brethren is a black thong.
The fact that Koji is wearing this and not attacking Joe would imply that he is not competing in the Gerrabacco Tournament, merely spectating it while also touring Aeter.
Koji has no dialog with Joe and is not really supposed to be in the shop. But he does become open to sex when approached.