..I think the one who missed the joke was you. Sakuya has a spell card named 幻世「ザ・ワールド」 because Dio's stand is ザ・ワールド. So when you say "ZA WARULDO" and it's Sakuya, you should say 幻世「ザ・ワールド」.
mario1277 said: You're only supposed to use that phrase when Kenshiro is present, but then again JoJo's Bizarre Adventure is as badass as Fist of the North Star.