She isn't really a hollow, after she ate other hollows. she then became an Arrancar in her adult from, with reason and logic. She is also an Espadas her original number was 3. 1-10 where all
Espadas. I was wonder why she has a child from anyways grimjow was more of an animal then human. I was wonder why but not clue.
So hoping to know she still alive, Ichgo mentioned her can feel what people believe in their hearts. When he was fighing Gin he mentions something like this. I'm pretty sure he would just randomly pick up neil with out thinking first even if she was in child from. Neil said she hates fighting though. In any case Nel wouldn't appear in the arc we're reading, what would be the point? Ichigo can't see her. I don't think she'll be forgotten, but same way than Rukia is absent from this arc, so is Nel. Maybe in next one she could reappear.I don't think Nel is in her "childish" mind anymore, I'm sure she remembers all about her "adult form" for now.
Nel is playing infinite tag with Pesche and Dondochakka on the roof of las noches, trying not to fall through the holes. It would be funny if the ones chasing them were either Grimmjow or Nnoitora. Though when Nel faded out and so did Nnoitora it looked like she had regained her memories in her child form. She'll be back later in the series, she has an important part to play so she will.
Love to watch some exciting Japan manga on the internet, but not all the manga are free online. Actually we have not to watch the exactly resource,we can also watch some good manga analystic articles. Yes, those articles are all based on the authors original mind, but also have some own opinion, even have some new idea, read those manga online knowledges, you can keep yours mind open.