Why does seeing what I saw, not even surprising? There's seems to be stuff like this happening now and then, at least from my perspective. Rakheid is the son of Zeref and possibly Mavis somehow. And there's always a bit of talk of how he lived his life the way he's lived, and why is he exactly the way it is. Ridiculously powerful, a hatred so high or whatever it is that's it always seems he's impossible to beat. Not to mention that they only way he can be stopped is by a certain individual.
Regardless, this doesn't bode well for FT. And next chapter, something's going to happen to Natsu it seems.