Tbf they all had full fights, Leo is a fraud because not only did he want to be saved for last he ended up losing to someone he had an immense amount of hatred for, like he was literally waiting hundreds of years for revenge only to end up with emotion growth and a hole in his stomach, Zero is really a fraud because he’s a pure offensive talent, it’s cool that he has a certain level of power but you can’t be seen as “top in the verse” if you have one of the worst defenses/ durability feats in the manga, Cu on the other hand Cu hasn’t really been on the offensive with exception to like 2 jumps and swings that got blocked/ countered let alone in his base form, on top of finding out that this was probably on purpose since his next form needs to have certain conditions met (as per Morrigan), completely different scenarios only tied together by people calling these charcters frauds, they’re really not comparable because Cu hasn’t had a chance to show what he’s capable of while the others have