With everyone busy fighting Madara and Obito, the "third power" Orochimaru is busy getting further power ups. Remember for the first time, Obito's hide out is unguarded.Madara, Obito, and Black Zetsu are all away and this leaves Orochimaru to go back to the hide out at his leisure. There are quite a few things Orochimaru has to gain fromthis...First off, two other resurrections have been foreshadowed by Kishimoto. Jiraiya and Shisui's DNA are both stored there. There is also Yamato and the White Hashirama clone which could meld into a perfect replica of the first Hokage to be Orochimaru's next body (Who knows, maybe having Senju DNA will allow Orochimaru to do his Eternal Rebirth technique without having to wait three years.). Lastly, he will have access to a myriad of Sharingan stored in the hide out and either use them for himself or use the DNA samples to Resurrect them. Orochimaru will be the final villain, believe it!