Jiraiya....here is his profile and some information:
http://www.leafninja.com/fullbio.php?p=Jiraiya
Honestly, Swamp of the Underworld would do away with Orochimaru. Handicapped Jiraiya was able to nearly sink a huge snake summon of Orochimarus', a healthy Jiraiya's Swamp would do away with him quickly. If not, then his Toad Stomach bind would. If not, then he can always go Hermit Mode (not that he needs to), and use Frog Song genjutsu to utterly own Orochimaru worse than Itachi and Sasuke have. It's pretty well known that Orochimaru is weak against genjutsu.
Hm. He has toad summons for both offense and defense, doton, katon, suiton, oil techniques, hair techniques, two forms of Rasengan, a genjutsu almost as broken than Tsukuyomi, that Orochimaru can't avoid, super speed and strength, along with taijutsu, while in Hermit Mode.....what else? Nami...take it from here. I have to go lol.