Since Mia played tricks on him in the game by giveing him items that messed up his character data in the games. It might be him again only as a mention though.
This is the report given to the Crimson Knights regarding Macha...
The character appears to be mentioning Piros, or a character that befell the same fate Piros went through numerous times in the game, in which Macha (Mia) tampered with their character's data.
In that case, it's just some random player, and not Piros himself. Piros is a graphics designer for the World, and in AI Buster 2, it's confirmed to be some random player of the World who isn't even given a name with no administrative ability.