Board Thread:Theories and Speculation/@comment-34678409-20180228015318/@comment-33286580-20180228045005

Kakashi certainly lost it.

according to Tobirama, the Uchiha's brain releases a special form of Chakra to awaken SHaringan and advance it. Kakashi is not an Uchiha so he does not have that Chakra.

to prove the point...

it so happens that none of Sharingan's power were really awakened by Kakashi. he started out with two tomoe and the third awakened when the eye turned into MS. the MS awakened because of the Obito and what he felt. the resonance cause both eyes to awaken third tomoe and MS. obito awakened Kamui and the resonance did so in Kakashi's eye.

Kakashi has shown nothing of his own with the SHaringan other than mastering the skills available to him.

in regards, since Susano can only be awakened by both MS, it probably has to do with that special chakra. madara being Uchiha had that special chakra and such could use Susano without eyes. Kakashi could only make use of Susano when he acquired Obito's chakra. Kakashi does not have the special chakra, so he cannot use Susano on his own or without eyes.