Finally caught up with manga. Still few episodes behind in anime.
So it is pretty obvious what Hiro is doing.
Tartaros started out with hype from Jackal killing the council.
Then Mashima had 2 demons take on Laxus and Natsu. Natsu and Laxus both won but with casualties and were hard battles.
So then Mashima had Elfman, Mira, Natsu, Erza all get captured. Erza also was tortured for however many chapters before the big fights started and FT started winning.
We had an extremely long prologue to this Alvarez arc. I consider everything dealing with rescuing Markarov, Mavis's story, Fairy tail zero, the prologue.
Now we are in part 1 of the original battles. Mashima is playing it off for the shock value. He hyped the Spriggins up and then allow them to get taken down easily so tertiary and quatriary characters (Bisca and Freed) get to have a moment (perhaps there last moment if the final bad guys are Zeref, Achnologia, and END).
Wharl and Azir are not finished. The whole point was to open Freed's jutsu and allow Brandish to get captured while Azir distracted everyone.
Remember Zeref telling Azir that he was not allowed to attack alone? And that they were going to do it Zeref's way. Even Brandish said it was not what she felt but what Zeref wanted her to do.
Attacking for fairy heart was probably a good way to motivate all his Spriggins, if he is having a hard time controlling some of them. Starting a war with Fiore and Achnologia is probably not good enough for them to fight unless they thought their reward was going to be an endless supply of energy. Some probably know they are being played, like August, who seems to be more aware of what is going on with Ragnork.
Because remember Zeref's intent is not just to capture fairy heart but attract Achnologia and bring Natsu despair.
It is more despair to give some hope and take it away than to merely crush your opponents. Brandish is getting close to the guild in order to find Fairy Heart and to bring Natsu despair by finding out probably who is best friends are.
On top of that, if Zeref makes the battle slow enough, other guilds have the opportunity to come and help. Increase numbers means that Achnologia will be attracted faster.
So next chapter will be a transition as the guild regroups from Ichiya's appearance right before the Spriggins make their presence known with some type of ending that hypes the next chapter. Then the next chapter will have some plot-twist. Then the next battles will start and fairy tail will either be crushed or more help will arrive in the form of Jellal and OS.
Back in tartaros, nobody thought Hiro would have Erza tortured like he did so I think he is building it up to have Markarov or Gildarts die when nobody thinks he will die because Lucy's monologue does indicate something horrible will happen, even if it is like 30 chapters of filler in this war before we get to that part.