Where did Danzo get his first Sharingan?

Question

In episode 358, Danzo uses Izanagi against Shisui and steals one of his eyes, meaning Danzo had a Sharingan eye prior to having Shisui's Sharingan eye. Nothing is known about how Danzo got his first Sharingan from what I've searched on the web, but we do know that he had one friend named Kagami Uchiha, whom Danzo considered to be one of his true friends.

Ruling out the possibility that Danzo killed Kagami in cold blood, is it possible that Danzo was gifted his first Sharingan from Kagami, possibly in the battlefield? Or could Danzo have gotten the Sharingan from somewhere else?

Answer 1

Its not clearly stated but from Shisui Uchiha article it states that Danzo have stolen an eye. Possibility him killing Kagami is very slim as, Danzo owes Kagami many times his life.

Quote from Naruto Wiki:

"Later, as Shisui prepared to make his move, Danzō Shimura, believing that simply manipulating the Uchiha's leader wouldn't end the conflict, chose to take Shisui's eyes for himself in the desire to protect the village in his own way. While Shisui effortlessly subdued Danzō at first, the ruthless elder caught Shisui off guard by using the forbidden Izanagi with another Sharingan already in his possession to break free and steal Shisui's right eye. As Danzō and his men surrounded Shisui to take the left eye, Shisui managed to escape."

I would say that Danzo have obtain the eye from somewhere else since in manga there was no shisui and danzo fight scripture. It was more towards fillers in shipudden. We all could only speculate, because in manga we just know that Danzo stole an eye from Shisui and that is the source of Danzo's sharingan when he fought with Sasuke. The part where and how Danzo obtained the eye from Shisui was not explained.