How was Aizen building up the Espada before getting the Hogyoku? In Season 10, after Nnoitra survives the Cero Doble that Nelliel ate and shot back, Nnoitra said that it had been years since Nelliel was an Espada.

From my understanding the Espada only started to form after Aizen got the Hogyoku and I don't see how it's been years since he took the Hogyoku out of Rukia.

So how was Aizen building up the Espada before getting the Hogyoku?
I believe the scene in question is from chapter 291 and episode 192, so this is what I'm going to work off of.

According to the wiki:


  The original Espada were already in existence sometime before Aizen's defection from Soul Society and acquisition of the Hōgyoku. 


So this would mean that Aizen did not have either Hōgyoku before the Espada were being gathered.

Then to answer the second half of your question, in the scene you mentioned Nnoitra is talking about how it has been years since Nelliel has taken her full form as an Espada due to the trama he inflicted on her long before rendering her appearance to that of a small child.





So in this instance he was not saying that it had been years since Nelliel had become an Espada, but that it had been years since she returned to being an Espada.