Thread:Signas501/@comment-1783453-20190819201327/@comment-3234545-20190906194012

You're misinterpreting what Kazuya is saying. When he says "I'm of the World Arcana now" he meant "currently, I'm equipping a Persona of the World Arcana." That's why his next line is "What do you think of my strength?", as a reference to the fact that in P1 the World Arcana Personas all have high Strength stats. The manga never reveals what Kazuya's Arcana is, but if anything he's an Emperor for the virtue of being born out of Naoya.