Isshin because Ryuken doesn't really have any feats.
Ryuken barely has any feats, Isshin wins.
Not only does Ryuuken has no feats, he gets killed.
This feat alone makes Isshin the winner
Also this is how the fight would turn out.
Based off feats Isshin wins. Based off hype Isshin wins. based off common sense Isshin Wins.
Ryuken wins because he wants his revenge on Isshin for stealing Masaki (I'm kidding, don't take me seriously).
@bigz007: he still a jealous pain in the butt that Isshin should Getsuga Tenshou away from Karakura
Isshin finger flicks him
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