Sekiro: Shadows Die Twice – Part 12: Folding Screen Monkeys
Before the next boss, go back to Ashina Outskirts and purchase items from the merchant. Then, go to the idol and head back to the main hall. There is a bell. After you ring the bell the fight will kick off, but this is not an ordinary one. You have to catch/kill some special monkeys. We recommend that you take out the invisible one first. Ring the bell if the monkey-hunt is not going good.
Once all the monkeys are finally dead, you’ll get another memory and another ninjutsu. Go to the idol and spend the memory earned. Then talk to the lady inside. She’ll give you the Mortal Blade and some rice.
Go out and make your way up to the door shown in the picture below.
Open it up and notice that you can now kill those ugly looking enemies with a scorpion tail. Test your sword and farm a little bit. Then find an idol in order to travel back to the Serpent Shrine and arrange your master skills as long as you have any of them. Finally, go out of that place and find another idol positioned down the hills.