Orochimaru... if he wanted Immortality so bad why didn't he study Hidan and his cult? There must be a deeper reason on why he wants Sasuke and his Eyes. I feel like Orochimaru can turn out to be the final villain still... heck he might attempt to takeover Madara's Body. Orochimaru's Body is now made out of Zetsu/Senju Cells... so that should be a power boost to him regardless.