I think she's Erza's mother too. The way Neinhart referred to her makes it look like she's her mentor or someone who he highly appreciates. I don't think that kind of relationship can be formed between two "teens" ...
And the way Brandish put them side by side, strongest man & strongest woman, I guess one needs a lot of time to get that tittle.
Still though, August being the strongest "individual" clearly indicates that he's stronger than Eileen.
Well as I said before I originally thought there was a personal connection between Erza's parentage and Neinhart because of the way he reacted last chapter. However as I explained that's not really the case anymore as we have now more info on the matter, namely that Eileen is even amongst the Spriggans considered one of the top members. Neinhart is a night, so that he referred to her as "lady" is rather common, but that counts even more so when you consider she's supposed to be higher than him. So I think now that Neinhart's is just the result of the both of them being Spriggan rather than being personally connected. IMO it would be quite the buzzkill if Neinhart would be Elieen's apprentice or something. My first impression of her is also not someone who would accept someone like Neinhart.
What's also interesting is the title of the next chapter: the monstrous six. I wonder if that would refer to the remaining Spriggan? There are still 5 remaining if you don't count Brandish, so it doesn't fit that well, however that depends on how you view it. If it indeed refers to the remaining Spriggan, well you practically have a 3-layered structure of their group: the "lesser" 6, the "monstrous" 6 and the latter includes the strongest male and female mage. Currently there is still one completely unknown Spriggan; August, the strongest male; Eileen, the strongest female; Imber, Zeref's right hand so assuming he's a cut above the rest is acceptable; and Bradman, who seems to have single-handedly beaten Saber and Pegasus.
Now for the 6th member, well that depends. It's possible that one might have already been beaten like Serena or that it's Brandish. The reality is that most of the Spriggan that have been beaten so far had powerful magic, but still the only one I truly found terrifying was Dimaria. Of Jacob, Azir, Neinhart and Wahl some had more interesting abilities than others, but in the end I could see them as being "lesser" than people like August and Imber.
This was a fun chapter.Although I have a little complain.Ninehart's buildup was a waste imo.This guy disobeyed Zeref and was shown 2 times in a badass silhouette.And then he called Dimaria and Wahl as pathetic.He had the most hype after August as character.I dont know if Hiro changed his mind or he just wanted to hype Jellal, but Ninehart was not worth the buildup.Wahl and Dimaria are more dangerous than Ninehart.
Apart from that I loved Jellal this chapter.His magic is badass and the fight shows he is above spriggans, which is good bcoz this guy targets Zeref.You cant target Zeref if you are not stronger than his henchmen.
As for Eleen, I am pretty sure her along with August are gonna kick the most ass from Spriggan side.Unless you count Bradman crucification few chapter back
Yeah Neinhart was a bummer, though I don't really see how he had much buildup and certainly not how he was hyped the most after August. He was only mentioned twice. The first time in Alvarez where they were summoned for a meeting, one he didn't attend and he was not the only one. In fact around 1/3 of the Spriggans weren't there and the 2nd time was when his silhouette was shown. I was also expecting something very differently when I saw that silhouette, but in the end you shouldn't pull this out of proportion. Azir, Dimaria, Brandish, August, Eileen, Serena, Wahl and Inber seems to have had much more buildup/screen time than Neinhart. At this point I only rate Jacob lower than Neinhart in that regard. I would be far more disappointed if Serena indeed would already be out of the picture or that the remaining unknown Spriggan would be dealt with as swiftly as with Jacob and Neinhart as I expect something special of the last one.