Is there something we don’t know about Shanks’ sword? (E1082 SPOILERS)

I didn’t catch this from the manga, but from this attack, it seems like there is something Shanks does with his sword to project his haki. Is Shanks’ haki truly that strong and accurate or could the sword somehow be a key instrument to his feats? I think it'd be interesting if we found out some of the Red-Haired Pirates use S-tier devil fruit-infused weapons and were chilling in marineford.