Orochimaru easily takes this.
Orochimaru trained sasuke in his kenjutsu, and we already know orochimaru is infact a skilled swordman himself. Kabuto's fight with the uchiha's gave us knowledge on how oral rebirth could be used offensive wise; thus giving orochimaru more methods to kill danzo. Danzo only has 10 minutes to kill orochimaru before he's slaughtered. With orochimaru attacking from one side, snakes attacking from another, and kusanagi in reserves to aid in any way possible, danzo will have a very hard time. In fact, orochimaru's paralyzing genjutsu can be very helpful in this battle as it'd give orochimaru enough time to move in on danzo... the same way sasuke had quuite a bit of time to move in. According to DB, orochimaru's as fast as hebi sasuke. That really doesn't help danzo out here, at all. This match up is one sided in orochimaru's favour.
Danzo can't kill orochimaru in 10 minutes. once izanagi drops, so does danzo.
>Inb4 KA oneshot