Doujun

Doujun is a side character and a minor antagonist in Sekiro: Shadows Die Twice. He is one of the quest-giving NPCs in the game. He is also a supporter of Genichiro's cause.

History
Doujun was once a Senpou Temple monk, though its likely he deserted in order to learn medicine under the guidance of the skilled doctor Dogen, just like Emma.

He became a surgeon of the Ashina clan, acting under Genichiro Ashina's orders, as they seem to have similar interests. During his training with the late Dogen, Doujun becomes has becomed obsessed with searching for ways to replicate the substance that are the resilience-granting Rejuvenating Waters. He also developed a second, much darker personality - Dosaku.

Following the straining victory of the Ashina clan, Doujun would be encouraged by Genichiro to quicken the pace of his experiments and thus, many innocent clan members are sent in the Abondaned Dungeon, only to crawl out as insane, rotting monsters.

Doujun is encountered later on by Sekiro, who is on a mission to obtain the Red Mortal Blade. If Sekiro chooses to talk to him, he gives the shinobi a series of requests. Sekiro can choose to kill him, ending his questline prematurely.

If Sekiro does go along with Doujun's plans, then he will either send Kotaru or Jinzaemon, so Doujun could experiment on them. At the end of his questline, Doujun is consumed by madness and begins experimenting on himself. Sekiro can then encounter Doujun and Kotaru or Jinzaemon, who have red eyes, signaling that they have been infested by the Rejuvenating Waters.

Personality
At first, Doujun appears as a humble and polite individual who seems ambigious and sketchy at worst. However, as the questline progresses, Doujun begins to degradade and his true madness and pride are unveiled. Like Genichiro, he is obsessed with obtaining immortality and he does it at the expense of everything and everyone, despite realizing how immoral his actions are. His alter ego - Dosaku, represents that obsession, his pride and his willingness to throw away his humanity. In the end, like Genichiro, he is just under deluded soul, desperate to change fate.

Quotes
"I am Doujun. I've been tasked with the preparation of a medical treatment using the rejuvenating waters."

- Doujun introducing himself to Sekiro

"I'm sure the master...will be ecstatic...even if, I am not. Try as I might, I'm unable to muster the same level of enthusiasm."

- Doujun sharing his doubts

"Ah...I am so sorry...Master...I've failed you."

- Doujun's dying words