I think if the purpose of killing the Admiral was to make us think for certain that Xebec was uber powerful, it would not be this offpanelled vagueness.
If he had showed Rocks standing over the defeated, dying Admiral, sword in hand, no hostage or anything in sight, barely a scratch, that would do the job without any real debate.
This? The clash with Harald is the real, undeniable powerscaling feat. But breaking into Imu’s room, destroying the gates of justice, winning Davy Back fights, stealing CD gold, and murdering an Admiral, I don’t think that is necessarily powerscaling. It is more personality scaling. We’re seeing why Rocks is this wildly audacious figure that challenged the world so much that his name was removed. But I don‘t think it’s necessarily needing to be viewed in a powerscaling lense.
The clash with Harald, Sengoku describing him as Roger’s greatest foe, his swordsmanship, Kaido’s five figures, that’s more powerscali g that character related.
Of course, they all combine and to be clear, it’s definite that Rocks was a PK level figure.
But this Admiral murder, I can’t help but think it’s pointing to another parallel with Teach- unsavoury, backstabbing behaviour. Blackbeard didn’t just beat Ace, he also murdered Thatch and Whitebeard in circumstances that really had little to do with powerscaling at all. Maybe that‘s the parallel we are meant to draw.