The Sabimaru Prosthetic Tool is one that you’ll definitely want to grab in Sekiro: Shadows Die Twice, especially if you want more versatility and agility in your fighting style.
To find where Sabimaru is located, you’ll want to head out to the Ashina Castle Sculptor Idol. From there, look up the giant staircase at the massive keep standing in your way.
Your goal, for now, is to reach the top of that building. To get there, make your way to the rooftops on your right, eventually making your way to the top of the building in the furthest back, right-hand corner of that area that has a feather-laden enemy perched atop it. Turn back towards the staircase, and you’ll see you can grapple to the top of the giant keep now. From there, you’ll have a bit of a long walk.
Keep pushing across that rooftop, past the staircase, and hang a right at the end of the available rooftop space. You’re going to encounter a ton of those feather-laden enemies here, and various kinds of them, so be on your guard. They are fast, attack in groups, and can cover long distances with ease. If you’re just here to get your prize, barrel through the area as quick as you can, following the grappling lines as you go. You’ll be looking to land on the rooftop that overlooks a large retention pond. From there, turn right and you’ll see a grappling opportunity that leads to the inside of the building, directly to the ‘Upper Tower – Antechamber’ Sculptor Idol.
Once inside, follow the natural path while wiping out the enemies until you come upon a large, open room from which you can see all the way down to the ground floor. Grapple onto the beam that spans the opening (you’ll have to jump over the railing to do so) and pivot until you see the four guards standing way beneath you. Lock onto whichever one you believe will be most problematic, jump off, and deal a Deathblow. Polish off the last three guards and make your way through the doorway that the one guard was standing in front of, and the other three were looking at. Inside, you’ll see some items, a pathway to leave, and a chest. Open the chest and Sabimaru is yours!
Same process as all the other Prosthetic Tools here. Head back to the Sculptor at the Dilapidated Temple, have the tool fixed on your arm, and assign it to an open slot. And that’s how to find and equip the Sabimaru Prosthetic Tool in Sekiro: Shadows Die Twice. Sabimaru allows you to have a secondary blade, and it costs one Spirit Emblem. Enhancing it to the Improved Sabimaru greatly increases its functionality and allows you to fluidly chain combos together and truly mix-up your style during fights.