User blog comment:Sosuke Aizen008/Maybe Starrk or Szayel or Nnoitra./@comment-11003280-20130809101858/@comment-11051098-20130812205724

The only Espada whos earlier forms we have seen, are Starrk/Lilynette, Baraggan, Harribel, Ulquiorra and Grimmjow.

Grimmjow as an Adjuchas, Harribel as a Vasto Lorde, Baraggan and Starrk/Lilynette I don't know... and I'm sure I read somewhere that Ulquiorra was "born" Vasto Lorde.