Zoro’s Hiryu: Kaen was incredibly impressive. It was so potent that it terrified Big Mom (a top tier swordsman in her own right) and made her warn Kaido to dodge.
We see Zoro’s Haki overflow through his sword by an insane amount.
Contrast this with the overflowing Haki we see from Prime Whitebeard and Roger.
Zoro’s Haki was overflowing to an even greater degree.
Just witnessing Zoro prepare the attack had Kaido shook:
Kaido heeds Big Mom’s advice and gets out of the way. The slash proceeds to travel over a kilometre and slash one of Onigashima’s horns. Said horn was several hundred metres thick.
As far as I’m aware, this is the most accurate scaling of Onigashima:
As you can see from the picture above, the skull of Onigashima without its horns is near 2 kilometres tall (a bit under twice the size of the umbrella).
The horns further raise its height by several kilometres.
Between the rooftop and the horns we see several mountains. The horn should be hundreds of metres thick, and the distance between the centre of the rooftop and each horn should be over a kilometre.
Zoro’s Hiryu Kaen was capable of travelling over a kilometre and slicing through a horn several hundred metres thick. In terms of sheer destructive capacity, Hiryu Kaen has been by far the most impressive of the Supernovas attacks.
Both in attack potency (terrified a top tier swordsman and caused the invulnerable Kaido to dodge) and destructive capacity, Hiryu Kaen is beyond the realm of One Piece high tiers. It’s a legitimate top tier attack.
*Theory by Cinera
