User blog comment:B214/Chapter 503: The Last Sight Seen/@comment-5303512-20160926122648/@comment-1359322-20160926142815

Every single Etherious in Tartaros would have no reason besides killing Zeref too, yet they killed many people some just for fun, so no that's a flawed logic too. Tartaros' Demons are Etherious, Natsu is an Etherious too being made differently isn't a proper excuse that's like saying because 2nd Generation Dragon Slayers are made artificially, they aren't Dragon Slayers like the 1st or 3rd generation ones.