Candor said:
I don't know, something seems wrong here. The first 2 pages seems more "that guy is a guy who came and made things worse than they already were" , Yama is talking about himself in the 3rd person PoV but changed it to the 1st when the panel of him being cut in the present appeared, and if you remember Bach said to Yama "Gotei 13 was more of a bunch of murderous thugs" which means Yama came to SS and made things worse than they already were by making Gotei 13 --> Yama feels regret for something that happened at that time with the last line..? The last line is what makes it not that clear, in both versions they have the same meaning, it seems if he appeared again it'll be the last time I use Bankai (die), question is just like you said, how did he know he's gonna die when he uses Bankai again?
I don't remember Kubo saying Kenpachi will get bankai btw, where did you read that?
well, whatever the case we'll just have to wait and see.
Also, I was talking about this http://www.animenation.net/forums/showthread.php?t=246152
sources from here and here