To those who asked the question. I guess his aging is like an infection. So putting the arm inside of him does the trick.
I dont mind the way he ends at all. his power is rigged. In such case, its really best to use it against him. Hachi might be the unique person who can do a space jutsu...oops, wrong manga...whatever u call it. Its his expertise. Indeed espada 7's death still is the best (though hardly making sense). "a taste of your own medicine" never get old in my book. Its classic.
Killing time while waiting for the next chapter. OnePiece, that is.