The Rin'negan, as shown in the canon anime, can be used to control corpses via chakra links, making them "paths" of the true rin'negan holder. It is most notably seen for the chakra connectors to be piercings being fed life-sustaining chakra by rods in the body of the puppet-master.
The real person must be hidden as they control the "paths," unable to move due to the chakra-connecting process.
The paths must have piercings, or someway to give them chakra to be "alive."
The paths can only be a (1) NPC, and the rest must be acquired by killing the site's members.
There is a strict, five Rin'negan users at one time. If one of them is completely killed, meaning all paths are gone, they must make a character in a different clan to allow fairness in using it.
The Paths must be obtained in the forums for those OC Characters with Rin'negan, so no posting in your app. "Bloodline: Rin'negan (Animal Path)." If you put that, we will deny you straight out.
There can only be (6) Paths at one time for any Rin'negan holder.
The Rin'negan is the only way for someone to have paths.
Gravity Release can only be: 1) earned, or 2) allowed by Nagato "Pein" Fuuma. Since it's a Rin'negan Ability, people without Rin'negan who use it won't have the ability to use it so often, or it will be less powerful.
Rin'negan Path System:
(1) Path: This may be a registered user, or NPC you killed. This is obtained at Genin ranking, not allowed to have many jutsu. It's attacks won't be very strong, needing a greater amount of chakra to use techniques because of the inexperienced nature controlling the path.
(2) Paths: This may be a registered user, or NPC you killed. This is allowed at Chunin Ranking, allowing the controller to split their skills in half with the two. They will have better control by now, able to use chakra, and ninjutsu with them at a lower cost of chakra than when they were inexperienced.
(3) Paths: This, like before, may be a registered user, or NPC you killed. This is allowed at Jonin Ranking. With the expanding of their chakra, they can use the Ninjutsu far more swiftly, having excellent control amongst them, with a furthering of Ninjutsu knowledge.
(4) - (6) Paths: Read above for how to get. These are allowed for people whom undergo extreme training, using all three paths at once. This isn't simple though, as they have to survive a fight with their Clan Leader for 3 Pages. As they get more paths, their attacks will be stronger, and their range of sight in a battlefield greater. Once they reach six, they must wait for one path to die completely, meaning it's destroied; then, the controller can collect and make a new path.