Xebec when using the attack that CUTS the island apart has literally the exact same sound effect as when Miahwk cut the frozen wave at Marineford.
"Xebec aint cutting, hence he is not a real swordsman even if he uses swordsmanship" cope? Done
"Xebec uses a boxing glove / has a gun hence he is not a swordsman" cope is done too by the way. Xebec was protecting hismelf, Eris, and Teach from his dad and grandmother and an arm of demons as well as two Holy Knights.
There is literally no scenario where he would use anything but his strongest fighting style in that scenario and what does that man do? Does he unleash his Haki magic? His Haki Domain Expansion? His Haki Sussanoo perhaps?
No? He just swings his swords and cuts people?


Peak chapter.
Xebec would beat his cowardly sons ass by the way for betraying the one friend he had that would face the literal devil with him. That man MUST be ashamed of how his boy turned out. No shot he co-signs any of the moves Blackbeard did to get where he is now given the characterization Oda gave him.