So why haven't we seen any demons yet?

[DarkSoulz]

We already know that Zeref created demons and he wanted to crush Fiore to the point of using all his forces to attack Fiore which at the time many Sprigaan's said was an over-kill. If he really wanted to over-kill them that badly then why not use his demons, he did say he will show Natsu "Despair" and he can do just that by unleashing his demons. At this point I don't think he can control the demons or they won't listen to him, maybe they are all royal to E.N.D?.

 

[Nemispelled]

We have seen demons. The Etherious demons during Tartaros.

Those were demons straight from the books of Zeref.

Besides E.N.D., Mard Geer was the strongest demon Zeref ever created.

Deliora and Lullaby were also demons from the books of Zeref.

 

[Axiomus]

We already know that Zeref created demons and he wanted to crush Fiore to the point of using all his forces to attack Fiore which at the time many Sprigaan's said was an over-kill. If he really wanted to over-kill them that badly then why not use his demons, he did say he will show Natsu "Despair" and he can do just that by unleashing his demons. At this point I don't think he can control the demons or they won't listen to him, maybe they are all royal to E.N.D?.

I always saw every one of the etherious leading up to END as experiments that he cast aside. The easiest answer to your question is that he already had the Spriggans, who are way more powerful than his demons. One of the Spriggans has the ability to use all the curses, and he wields it at a Spriggan's level of power. Even if Zeref did need his demons he could just ask Bradman to do whatever it is he needed.

Another easy answer is that all the demons have been defeated during Tartarus.

 

[DarkSoulz]

We have seen demons. The Etherious demons during Tartaros.

Those were demons straight from the books of Zeref.

Besides E.N.D., Mard Geer was the strongest demon Zeref ever created.

Deliora and Lullaby were also demons from the books of Zeref.

I mean in the war. Zeref created the demons, if he doesn't use them in an all out war then when will he?

 

[Nemispelled]

I mean in the war. Zeref created the demons, if he doesn't use them in an all out war then when will he?

Oh. Well since Mard Geer was his strongest demon, then I'm betting that all his other demons are probably mostly fodder.

It's probably no use at this point since Team Fairy Tail has Gray who is a demon slayer and can wipe out a whole demon army by himself.

 

[Arjuna]

I mean in the war. Zeref created the demons, if he doesn't use them in an all out war then when will he?

Apart from END no other Demon is alive now.Only Etherious Bradman was alive and fought in the war but he is dead now.