Black Receiver

Black receivers, created and used by those who possess the Rinnegan, act as high-frequency chakra demodulators, allowing users to transmit their chakra into these receivers, and by extension, into those whom the receivers have been embedded in. Chakra can be transmitted across vast distances, though for best results the user should be nearby and at a high elevation. Black receivers disintegrate if their creator is killed or incapacitated.

Origin
The exact source of the black receivers is unclear, having been seen produced through various means:
 * Rinnegan wielders are able to generate them from their own bodies, usually their hands.
 * Nagato's Six Paths of Pain can also generate them from their bodies.
 * Madara Uchiha produced a black receiver from Hashirama's artificial body, calling it his will in physical form and telling Obito Uchiha to use it with the Six Paths Technique.
 * Black receivers have protruded from the Demonic Statue of the Outer Path's midsection at times, on one occasion piercing Nagato's back and draining his life force. He was afterwards able to control the Demonic Statue.
 * Black receivers have sprouted from Obito's prosthetic limb on several occasions, typically while his actions are being controlled by others.
 * As the Ten-Tails' jinchūriki, Obito seemingly converted his Truth-Seeking Ball into six black receivers in order to perform the Six Red Yang Formation.

Usage
Users can produce black receivers in various shapes and sizes to fit the situation. The most frequently seen usage has been as part of the Six Paths of Pain, where the user embeds up to six corpses with chakra receivers, which can optionally be fashioned into body piercings, in order to reanimate and take full control of them. The user is then able to perform jutsu through the bodies and shares their field of vision. Creatures summoned through the Animal Path also have these body piercings, suggesting a similar manner of control. The receivers implanted in Obito's Six Paths of Pain doubled as a means of temporarily binding the chakra of the tailed beasts sealed in the Demonic Statue to the bodies, granting them the abilities of a jinchūriki.

Black receivers can be employed offensively, wielded from the hands similar to swords. By stabbing a target with these receivers the user can transmit their chakra into them, hindering their movements if pierced with only one receiver, and completely paralyzing them if pierced with multiple. Simple contact with the receivers can apparently incur the same debilitations, an effect only other Rinnegan users are immune to. If the user is able to create a strong enough transmission into a target, they can potentially control the target's movements, though it is possible for the target to resist this effect provided their own chakra is powerful enough. Offensively employing receivers through the Six Paths of Pain carries a risk to the user, as sensor types can trace the transferred chakra back to the user when pierced with one. In an effect similar to that of the Truth-Seeking Balls, black receivers appear to cause permanent damage to reincarnated individuals, with their bodies being unable to repair the damage until the receivers are removed.

Obito is shown employing black receivers fashioned into giant stakes as projectiles, ejecting them from Kamui's dimension to pierce and pin targets. He can then transmit chakra chains into the receivers to further strengthen the binding.

Trivia

 * When Obito's Six Paths of Pain enter Tailed Beast Mode, the black receivers relocate from the jinchūriki's chest to the tailed beast's neck.
 * In Naruto Shippūden: Shinobi Rumble, Pain's Black Needle Stab temporarily reverses the controls of those stabbed with black receivers.
 * Naruto Uzumaki made a similar usage to these rods when he shaped his Truth-Seeking Balls into rods and used them to immobilise Black Zetsu, preventing it from even escaping underground.