When Sasuke first activated the Susanoo with 2 MS it didn't really resemble the Complete Susanoo. But when Obito gave Kakashi his eyes he activated Complete Susanoo. Why did it take so long for Sasuke to activate Complete Susanoo.
How could Kakashi make a Perfect Susanoo with only two MS when Sasuke needed a Rinnegan?
1If you want to make a perfect Susanoo then go ahead. Maybe Sasuke wasn't even planning on making it a perfect Susanoo. Also you don't need the Rinnegan to make any type Susanoo, you just need both Mangekyou Sharingan.– Akira MahisaseruSep 20, 2016 at 3:03
I think my answer here might answer your question. anime.stackexchange.com/q/36148/18881– Josh McMahanSep 20, 2016 at 17:27
Once a user awakens the Mangekyō in both eyes, or the ability of both of their eyes, they are able to perform Susanoo.
Sasuke could make a "perfect" Susanoo once he got ability of both of his eyes. One probable reason why he didn't use it right away could be the fact that Susanoo does use up a lot of chakra and he might be saving his chakra.
The Mangekyō Sharingan's abilities drain a considerable amount of chakra when performed.
It probably requires training as well. We know Sasuke's Susanoo changed several times, and sometimes it overwrote the old form which was never seen again. While he probably had the potential to unlock it once he got 2 MS, he probably couldnt go beyond armored without more power and training. Kakashi also admitted that the Mangekyou Sharingan is strengthened by Six paths power (obito being 10 tails jinchuriki), which Sasuke also received (by Hagoromo himself) before using perfect Susanoo– RyanSep 20, 2016 at 15:41
Additionally, Madara was able to produce a Perfect Susanoo without the Rinnegan, in his fight with Hashirama.– RFKomosSep 21, 2016 at 12:48
Susanoo does have its own development stages but we have to keep in mind that each development stage needs a huge amount of chakra to accomplish. Considering the fact that Kakashi is a really skilled ninja, he could make a complete Susanoo by copying the way Sasuke was manipulating his chakra; afterall he is a copy-ninja. he had the skills he had the knowledge.Pretty sure he can get it to final form Sep 21, 2016 at 12:56
Reason 1: he probably didn't want to use Perfect Susanoo, he used a full body Susanoo. In Naruto Shippuden, during the 4th Great Ninja War, Sasuke's Susanoo fused with Kurama, when that happened, Sasuke got wings. After he did that, you know that little thing when Sasuke stands on Susanoo up high that covers him? That's Sasuke using Perfect Susanoo.
Reason 2: maybe it's a simple "he didn't want to use Perfect Susanoo", or he didn't know his abilities of his Susanoo.
Reason 3: maybe he couldn't because probably his ability with 2 EMS isn't allowed for Perfect Susanoo, but if he has Rinnegan, he can.
This perfect susanoo is only available to those who perfectly master the mangekyou sharingan. Kakashi had the benefit of mastering one eye while obito mastered the other and when obito died and loaned those eyes, it was as if both obito and kakashi's experience was applied and as suck, they just had to awaken the susanoo in that state, while sasuke had to master not just his abilities but also those of itachi to awaken the susanoo perfect state, essentially having to master two pairs of susanoo. And interesting fact, that s shows that no matter the person, as long as a mangekyou sharingan is implanted, they can attain the eternal mangekyou sharingan as the perfect susanoo would likely blind the user of a regualar mangekyou sharingan instantly unless we speak about the pure sharingan of hagoromo and Indra. Or they may already be blind at that point due to practicing the mangekyou which requires regular use.
1Interesting fact, your comment about the Eternal Mangekyou Sharingan is wrong. Please do your research. Dec 4, 2016 at 3:45