I know he "showed" him dying but i don't think he's dead especially since his body was never found, I mean look what happened to grimmjow, he is apparently alive despite it seeming like he died. So i think he's still alive and still the strongest.
Plus to top it alll off he died to quickly and easily...Thats not kubo's m.o.
Very nice coloration Are Yamamoto's eyes glowing? Kubo did an effing great job on Yama's Bankai Enough power to destroy Juha Bach, himself and even Soul Society itself. I imagined his Bankai like a hell of flames, but this is so much better.