That's what Portrayal means, King's children had Emperor level Luffy and a YC1 Lucci struggling for their life against them :

Copenaker: ThAt WaS jUsT bAsE lUfFY
Against Kizaru:
Copenaker: No ACoC!!
Also Copenaker: Hahaha, emperor Luffy struggled against Seraphim although he didn't use ACoC at all!