Wonder if ol' Joseph Joestar could conjure up a plan to save Ashi and defeat Aku? I can just see it now!

Aku: Bwahahaha!!! This is the end for you, foolish human, now that I have defeated you-!
Joseph: Your next words are "The world, nay, the universe will be at my disposal!"
Aku: The world, nay the universe will be at my disposal! …What?!!
Joseph: It's quite simple, you black mould of goo! I knew the girl would have something like this happen, so I made a few countermeasures! I transferred a little of my Hamon onto the sword she picked up! And then it transferred to her! I also managed to tie a thin piece of string to her when she wasn't looking!
Ashi: ???
Joseph: Like so! Uses the hamon to temporarily disable the Aku essence, and yank Ashi to safety. Now your next words are "Bah! It doesn't matter, I still have the sword!"
Aku: Bah! It doesn't matter, I still have the sword! WHAT?!!!!
Joseph: You fell for it, hook, line and sinker! I attached a couple of rockets lying around this scrapyard when nobody was looking to the back of the sword. And all I have to do is activate them! Presses the switch that fires the sword to Aku, dealing significant damage You're a couple of centuries too soon to tangle with the likes of Joseph Joestar!

-Foolish Samurai! You thought you shared your first kiss with a perfectly normal, nice girl, but it was again I, AKU!
-AKUUUUUUUUUUUUUUUUUUUUUU!