1. 戦いとは, both sides are dead, injured, and pained. みを合うものだ
(War will be accompanied by death, injury and pain on both sides)
2. Pain is felt, pain is tested
(Feel the pain, think about the pain)
3. Pain is felt, pain is known
( Accept the pain, understand the pain)
This is the line Pain said before letting Shinra Tensei destroy Konoha.
Principle of control:
Puppet ninjas transformed from the corpses of six dead people. Each Payne's face and body are inserted with devices that can connect signals and conduct chakra. The black rod, the nail-shaped chakra receiver, and the six Pains can enjoy sight (Reincarnation Eye Passage), even if the enemy goes around the back of one of the Pains.
The other Payne will also monitor the enemy. Everything the Payne sees in the back is also what the Payne in front sees, and each Payne has the ability of the Samsara Eye. The main body of Nagato has a huge amount of chakra, and can control six corpses to fight, and the hell path Pain in it can resurrect the dead Pain. These can be regarded as the reasons why Pain is "powerful".
Nagato controls the black rods as chakra receivers by inserting them into his back. The Chakra Black Rod can also be used as a weapon, injecting one's own Chakra, and its power of reincarnation can confuse the Chakra of the person being penetrated.