Major Credits for this theory go out to the poster The Robot with Human Hair, who intially presented many of these findings. If you do decide to give reputation points, I would appreciate it if you sent some his way.
Susanoo is arguably the most powerful Mangekyō Sharingan Jutsu, and easily one of the most capable Jutsu in the Narutoverse. The past year, Uchiha Madara unveiled the most powerful rivative of this Jutsu with his "Perfect" Susanoo. Following the unveil of this technique, naturally, speculation arose among the fanbase as to whether or not Sasuke would gain this ability (or something akin to it) to be able to fight on relatively equal terms with Bijū Mode Naruto.
My own quest to find the answer to whether or not Sasuke would obtain the "Perfect Susanoo" led me to dead ends on the evidence side of things, but I was still fairly certain that Sasuke would achieve this Jutsu based purely on a plot perspective (Naruto and Sasuke being two sides of the same coin).
Yesterday, the poster The Robot with Human Hair made an interesting post in a thread where he introduced me to some new Mythology regarding the creatures that the appearance of Madara's, Sasuke's and Itachi's Susanoo's are based on. These creatures are known as the Tengu.
This is the describtion of Tengu as provided by Wikipedia:
Tengu (天狗?, "heavenly dog") are a type of legendary creature found in Japanese folk religion and are also considered a type of Shinto god (kami) or yōkai (supernatural beings). Although they take their name from a dog-like Chinese demon (Tiangou), the tengu were originally thought to take the forms of birds of prey, and they are traditionally depicted with both human and avian characteristics. The earliest tengu were pictured with beaks, but this feature has often been humanized as an unnaturally long nose, which today is widely considered the tengu's defining characteristic in the popular imagination.
Based on the simplistic definition of Tengu as per provided by Wikipedia (and my previous belief):
One would come to assume some sort of superiority of beaked Tengu based on the fact that they predated long nosed Tengu (things tend to get watered down over time), but Research by The Robot with Human Hair showed otherwise.
A detailed account of Tengu in Wikipedia mentions that:
In the Genpei Jōsuiki, written in the late Kamakura period, a god appears to Go-Shirakawa and gives a detailed account of tengu ghosts. He says that they fall onto the tengu road because, as Buddhists, they cannot go to Hell, yet as people with bad principles, they also cannot go to Heaven. He describes the appearance of different types of tengu: the ghosts of priests, nuns, ordinary men, and ordinary women, all of whom in life possessed excessive pride. The god introduces the notion that not all tengu are equal; knowledgeable men become daitengu (大天狗, great tengu?), but ignorant ones become kotengu (小天狗, small tengu)
Daitengu are often pictured in a more human-like form than their underlings, and due to their long noses, they may also called hanatakatengu (鼻高天狗, tall-nosed tengu). Kotengu may conversely be depicted as more bird-like. They are sometimes called Karasu-Tengu (烏天狗, crow tengu), or koppa- or konoha-tengu (木葉天狗, 木の葉天狗foliage tengu
According to this the long nose "Daitengu" are actually the superior beings, while the beaked "Karasu-Tengu" are said to be underlings of the "Daitengu".
Here are visual depictions of both:
The depictions of these two Tengu led me to analyze the appearance of the Susanoo's shown in Naruto.
There are two general Susanoo designs we've seen in the Manga:
Long nosed:
Itachi's Mangekyō Sharingan Final Susanoo
Naruto Chapter 552 Page 2
Sasuke's Mangekyō Sharingan Final Susanoo
Chapter 484 Page 9
Madara's Eternal Mangekyō Sharingan Final Chakra Stabilized ("Perfect") Susanoo
Beaked:
Sasuke's Eternal Mangekyō Sharingan Final Susanoo
Madara's Eternal Mangekyō Sharingan Final Susanoo
Note: The appearance of the Beak on Madara's Susanoo will be further discussed later in the thread.
After comparing the story of the Daitengu to Naruto I discovered something both strange and intriguing.
Notice how Itachi and Sasuke's MS Final Susanoo's are both long nosed and resemble Daitengu to a certain extent?:
Itachi's Mangekyō Sharingan Final Susanoo
Naruto Chapter 552 Page 2
Sasuke's Mangekyō Sharingan Final Susanoo
Chapter 484 Page 9
Is it a coincidence that the pinnacle of Susanoo for the regular Mangekyō resemble Daitengu, but the Final Susanoo's (unstabilized) for both EMS Madara and EMS Sasuke don't resemble Daitengu, but instead resemble Karasu-Tengu? Its weird in the case of Sasuke because his Final Susanoo while he had his Mangekyō Sharingan resembled a Daitengu (Greater Tengu) before. Why would Kishimoto want an allegedly more powerful Susanoo to resemble an inferior Tengu, instead of the superior Daitengu?
Here are Madara's and Sasuke's Eternal Mangekyō Final Susanoo's (unstabilized) once again:
Sasuke's Eternal Mangekyō Sharingan Final Susanoo
Madara's Eternal Mangekyō Sharingan Final Susanoo
One interesting thing I noticed was that Sasuke's Eternal Mangekyō Sharingan Final Susanoo has a beak that is noticeably more prominent that Madara's. While Madara's Susanoo also has a beak, It appears to be smaller in its size than Sasuke's (on a relative scale).
I then remembered that Madara's Final Chakra Stabilized Susanoo also resembled a Daitengu:
Madara's Eternal Mangekyō Sharingan Final Chakra Stabilized ("Perfect") Susanoo
Is it a coincidence that the pinnacle of Madara's Susanoo resembles a Daitengu? I think not.
This idea is the basis of my theory.
I'm of the belief that the Susanoo of a user will resemble a Daitengu when they have reached the pinnacle of Susanoo that can be produce from their eyes. My belief is that the reason Sasuke's and Itachi's Final Susanoo of their Mangekyō Sharingan's resemble Daitengu, is because those Susanoo's are the best Susanoo's that both of them can produce with their Mangekyō Sharingan's. Those Final Susanoo's are the pinnacle of Mangekyō Sharingan, and as such, resemble Daitengu (Great Tengu).
The reason I believe that Madara's and Sasuke's Eternal Mangekyō Sharingan Final Susanoo (unstabilized) don't resemble Daitengu, is because those aren't the absolute pinnacle of Susanoo that they can produce from their Sharingans. I also believe that the reason that Sasuke's Eternal Mangekyō Sharingan Final Susanoo has a more prominent beak than Madara's (resembles a Karasu-Tengu even more), is because his Susanoo is farther away from reaching its pinnacle. This is why Madara's absolute pinnacle Susanoo, his Chakra Stabilized Final ("Perfect") Susanoo resembles a Daitengu. That Susanoo is the pinnacle of Susanoo that Madara's Eternal Mangekyō Sharingan can produce.
As the manga progresses (unknown # of chapters from now), I'm of the belief that as Sasuke's Final Susanoo gets larger, its beak will become less prominent (resemble a Karasu-Tengu less), and once it stabilizes, it will have a long nose and resemble a Daitengu.
