Thanks to the extreme dearth of readable threads in the library these days, I thought I'd take a crack at making something provocative.
So here's my take on the powers of the Rinnegan as we know them so far.
, it might not be what you're expecting.
The Powers of the Rinnegan
What are the actual powers of the Rinnegan, you ask?
Let's make a list, and start off slowly.
First off, according to Jiraiya, the Rinnegan allowed Nagato to master all six forms of chakra - presumably the five elements plus one other - perhaps yin/yang.
Okay, moving on.
Second, the Rinnegan bestows upon its possessor the ability to see spiritual energy and beings.
Here, we see Pain observing the spiritual barrier that surrounds Konoha:
What suggests that this barrier is formed of spiritual energy?
Simple, with a village full of people who can see chakra with their doujutsu, we've never heard one mention of it before now. That's either a very strong coincidence or it's telling us something.
Also, the guys controlling the barrier wear Pope hats:
This obviously signifies the spirituality of the barrier they maintain. (Keep in mind I'm only 50% kidding here.)
Moving right along, we have Pain being able to see the Hell King Enma with his Rinnegan:
This is a being that cannot be detected by anyone else without it interacting with them specifically, much like the Shinigami.
Third we have... oh wait. There is no third.
That's it folks, that's all I've got for you.
Not convinced? Let's take a look:
Things That People Like to Pretend Are Gifted by the Rinnegan, but Probably Aren't
Jiraiya tells us that, as a child, Nagato expressed an unnatural aptitude for ninjutsu. The databook tells us that his hobby was creating and learning new techniques. Given the powers of the Rinnegan, he has an advantage over every other ninja in that regard.
Jiraiya does not tell us, however, that Nagato suddenly began manipulating the Six Realms of Metampsychosis.
He does not tell us that awakening the Rinnegan granted Nagato access to powers never before seen in the world of ninja.
He does not tell us that the Rinnegan comes equipped with a jutsu repertoire as the Mangekyo Sharingan does.
In fact, Nagato exhibits no signs of having inherited superhuman powers from his doujutsu in the three years that Jiraiya knows him.
Chances are, he didn't magically get his powers overnight.
The Six Paths of Pain
The Six Paths of Pain is a ninjutsu created by Nagato that we've all come to know and love (or hate, if that's your persuasion).
Each Realm exhibits unique abilities that seem to be well above the powers that normal ninja are capable of possessing.
On the face of it, these abilities seem like they must be powered by the Rinnegan as they are too powerful for a normal ninja to create.
But is that really true?
Let's break it down.
God Realm's major power is control over gravity and repulsive and attractive forces:
While this power is cool and - dare I say it? - godly, it has absolutely nothing to do with the spiritual nature of the metampsychosis theme that the Rinnegan seems to possess.
It's a fairly unique power, but it's not anything beyond what ninja should be capable of with ninjutsu. After all, the Third Kazekage had a power of a similar nature - the ability to manipulate magnetic fields.
Hell is able to control the King of Hell - Enma - to some extent.
But remember, this isn't the first spiritual being we've seen used in battle or have a contract formed with it.
Here we see Hiruzen use Minato's technique to summon the Shinigami - a spiritual being that, like Enma, is only visible to those affected by its power or, as I propose, a person with the Rinnegan.
So summoning such a being to do a ninja's bidding isn't limited to Pain or a possessor of the Rinnegan either.
Not much to say here. The dude is a robot. Nothing spiritual about missiles or cannon hands or explosions, so I'll just move on. Okay?
Human can apparently read a person's mind at incredible speed or even rip the spiritual energy from their body.
Now obviously, no one would think to create a technique to rip spiritual energy from an enemy if he or she didn't possess the ability to see that energy in the first place. So while the Rinnegan perhaps persuaded Pain to create this jutsu, saying that it is gifted by the bloodline isn't really founded.
Second, we have Pain reading the minds of others:
I think that Ino makes my point best here. Pain is simply using an advanced version of Inoichi's technique - nothing insidious or unbelievable here.
He just went about creating an interrogation technique to use and did a better job than the Yamanaka clan.
No surprise considering he's probably the greatest ninjutsu genius of all time aside from possibly the Sage of the Six Paths himself.
This one is a bit tricky, considering how complex Pain's contract is.
One theory is that the contract is gifted to him by his bloodline.
I don't buy that.
I believe it's much more likely that he subdued the animals he can summon (we know that these mythical beasts exist in the real world, just as giant, toads, snakes, slugs, and salamanders do), and killed them only to be brought back through his chakra rod technique and used to create his own contract.
It's fairly obvious that - like the bodies of Pain themselves - the animals he summons are dead and controlled just as the bodies are. They can even share sight and possibly other senses with him as part of his Six Paths jutsu:
Summoning is not an unexplainable ability. Pain just uses his summons in a different way than others. It's not that hard to understand.
Another easy one.
Sealing away ninjutsu has been around for a long time. I'm sure many of you can recall this memorable scene:
Once again, Pain has taken an ability that is available to all ninja and has perfected it to the highest level possible - or that we've seen.
It's not inconceivable that a ninja with Nagato's prodigious skills can accomplish this.
A Bit More About Pain:
The abilities of many of the realms do revolve around their stigma in the tradition of metampsychosis, but that doesn't mean that they are granted by the Rinnegan at all.
Nagato simply chose the Six Paths as a theme and went with it, assigning abilities to the bodies as they were named.
It doesn't have to be more complicated at that.
Jiraiya, Fukasaku, and Shima originally postulated that sharing sight was an ability of the Rinnegan, but I would argue that it is an ability of the Six Paths of Pain ninjutsu. Not only sight is shared. So are thoughts and presumably every other sensation. All they are is information being sent back to Nagato to be acted upon, after all.
Sage of the Six Paths?
So how does the Sage of the Six Paths come into all of this?
He created ninjutsu, and therefore most likely discovered chakra for what it is, right?
As we know from the fancy chart, chakra is a combination of body energy and spiritual energy.
Body energy is sort of obvious here. It's physical fitness and stamina. Any old person could figure this out.
But what about spiritual energy? How do you learn to control something you can't see or feel normally?
Then along came the Sage.
His Rinnegan allowed him to detect the spiritual energy in his body and the bodies around him, allowing him to mold chakra and create the first ninjutsu.
This also helps to explain why Nagato can have so much chakra. Since the Rinnegan is intrinsically linked to spiritual power, Nagato has an immense amount of this energy - possibly more than any other human.
That, or he is simply more efficient in its usage since he is aware of it.
In conclusion, we find that the Rinnegan's power is to attune its possessor to spiritual energy and allow him or her to use all six forms of chakra manipulation. Whether this is due to the connection with the spirit or simply a second ability, we can't be sure.
The Six Paths of Pain are not necessarily - nor even likely - a direct manifestation of the Rinnegan's power. More likely they stem from the amazing insight that Nagato has into ninjutsu thanks to his bloodline.
And thus, our study of the Rinnegan's powers is concluded.