I like how oda portrayed Xebec character, he is a true pirate in the sense his pirating ways are closer to reality than luffy's for example, he pilage, steal, scare the shit out of normal ppl and even went as far as Killing a navy admiral, on the other hand his pirating ways are not so "pointless" as he (acknowledging his Davy name inheritance) wants to dethrone the world goverment and Imu in particular ... which is exactly how nowadays teach is, that's the climax that oda wanted, you see Xebec, you like him, then you realize Blackbeard might actually resemble Xebec personality but with a more villanous twist due to his childhood difficulties.
He is in between.