User blog comment:Xilinoc/Ch. 568. Hear. Fear. Here 2/@comment-5147109-20140212234854

My two cents on Byakuya, I would say that in the first battle Byakuya kind of had the odds stacked against him, he had just had his Bankai stolen which had to be somewhat disorienting, not to mention the fact that very shortly after he was both hit with the fear which he was able to somewhat hold up against, and abruptly attacked by his own power. As stated by As Nodt most people collapsed into a screaming mess immediately after being hit by his thorns and Byakuya was still somewhat able to function. But now he's back, beefed up from the Royal Guard training, and he has his Bankai back, and let's not forget the last time someone attacked his pride (Rukia) he annihilated his enemy (Zommari Rureaux). But bottom line I believe if Byakuya was to have a defense against the fear it would very likely be Rukia herself, Byakuya himself has stated on several occasions that he puts his pride above all else, perhaps that can be enough to overcome that fear.