Board Thread:Questions and Answers/@comment-10922879-20130617143901/@comment-11051098-20130621224027

His Respira-technique is something different from other Espada, it might have made him the Primera Espada in terms of what damage he could do. But the Espada seemed to have been ranked by their reiatsu.

Stark/Lilynette had tremendous reiatsu, so much that other hollows died just from being near them. Even after splitting into 2 souls, it still seemed to happen. And even though Yammy was the Cero Espada in his release state, it seemed that he only became the strongest in terms of physical power and brute force.

I do think Ulquiorra could have been ranked higher when considering his Segunda Etapa form. From what I could tell of Halibel, Baraggan and Stark's performances and powers in battle, I think the sheer destructive power Ulquiorra possessed, could have made him the 3rd or 2nd or maybe even top Espada. Like his attack Lanza del Relámpago, although he wasn't able to completely control it.