Idk how i thought of these (maybe drunk off mountain dew and staying up so late my eyes hurt have influence) but here are some random idea's.
Pein: Obito who was saved by a rain nin, later leaving after Tobi offered to reunite him with Rin. Made the sky rain after hearing he had to capture and eventually kill his son.
Blue hair unnamed pein partner: Rin, never mentions what happens to her, left Konoha to see Obito again after being offered by Tobi during a mission, kakashi thinks she died on that mission. Noticed Pein making the weather show his emotions after hearing his new mission of capturing the nine tails.
Tobi: Uchiha Madara's son who rescue'd Obito from death after noticing his sharingan being used wanting him to further his goals. Used Rin to get Obito to leave hidden rain village to join him.
naruto = Obito and Rin son
Zetsu = Naruto's Brother
for anyone who stuck around to read all that.. yeah donno how i rly came up w/ these =P