How do you get Orochimaru?

You have to buy him in the store. I think he is the last person you can buy other than Sasuke with Sharingan, who is awesome by the way. If not try to complete the stories and will eventually show up in the shop.

1) Beat stroy mode
2) Unlock all characters before him
3) Gain 10,000 to buy another mission
4) Complete the new mission
5) Gain 50,000
6) Buy Orochimaru

First off, you have to clear Story Mode on any difficulty. Next off, you must have at least 10,000 dollars worth of money to buy Story 25 when Kakashi fights Orochimaru. If you beat the story, Orochimaru will be at the shop for 50,000 dollars. Try getting money through playing the game(Oboro mode highly suggested). Once you get enough, you can play as Orochimaru.
Hope this helps you out.