The true Pain is Nagato, he controls all of the 6 paths of Pain (which are actually dead bodies). He has the ability to remotely control any object using special chakra metals infused with his chakra (These are shown as piercing on the 6 paths of Pain).
He has the power of all 6 paths, plus the outer path (Gedo), he can revive people who recently died, and he also can take away people's souls using the Gedo Mezu.
There are also rumors that Naruto is Pein's nephew. It could be true that Pein and Kushina Uzumaki are siblings but Pein's original name was Nagato before it was changed because of his past sufferings.
Nagato is Pein, so if he was Pein, then Pein would already have the Rinnegan.
Konan is Pein's partner.
Pein is not a word in the English language. However, Pein is the leader of Amekagure in the anime of Naruto.
Pein's fullname is never revealed. Pein is really Nagato, and just an alias that was created.
Nagato give pein the rinnegan
No Neji does not fight pein.
Pein is taller but not by much.
I heard that Konan and Pein make a great couple, but in Naruto Shippuden, Pein dies without Konan saying she liked Pein, there is no proof.
No, because Pein killed Kakashi, proving one thing. Pein is stronger.
No, Tobi does not kill Pein. Pein sacrifices himself when he revives everyone he kills in Konoha.
no. pain is leader of the group physically, yet the founder and true leader is Tobi/Madara Uchiha