Q: I have a question regarding Stark. How strong is he actually? I can't imagine him having higher (stronger?) killing power than Barragan in terms of special ability, so does that mean he's superior when it comes to Reiatsu?
Also, regarding the timing of him joining Aizen's forces, judging from the way it was depicted it appears that he joined the Espada after Aizen had already acquired the Hogyoku.
If so, then:
1) His reiatsu was so strong prior to splitting that even someone of Aizen class couldn't detect it
Or
2) Aizen had sensed it, but considering his strength it could have been difficult to deal with him, so I assume that Aizen decided to simply leave him be until the situation had settled.
I really like Stark, but he doesn't appear much and I have little hope that he will return in any future media. So I would like to know more about him!
Kubo: It's 2). I think Stark's charm is that he's a guy who's difficult to read.