Lone Shadow Vilehand is an optional mini-boss found in Sekiro: Shadows Die Twice.
Located in the Upper Tower of the Ashina Castle during your second visit to the region, he’s found in the same location where you fought Ashina Elite – Jinsuke Saze earlier on in the game.
From the Upper Tower – Ashina Dojo Sculptor’s Idol, look through the door and you’ll see Lone Shadow Vilehand stood in the next room with his back to you. Don’t get all excited and run straight in for a stealth Deathblow though, as there’s an enemy hiding to the left hand side of the door. Instead, creep into the room and stay tight to the left hand wall and you’ll be able to sneak up behind the purple enemy. You can use the Puppeteer Ninjutsu here if you want, which will cause the enemy to fight alongside you and give you a two-on-one fight in your favour. The fight is very easy if you do it this way, so it’s definitely recommended. If you want to act the tough guy, hit the purple enemy with a stealth Deathblow to trigger a one-on-one boss fight and read on.
Even in a straight one-on-one fight he’s still pretty easy to kill, so you shouldn’t have too much trouble with this one. It’s all about Deflecting his attacks to fill his Posture bar, and you should have got the rhythm of Deflects for his attacks perfected by now after numerous fights against Lone Shadow enemies.
You do need to watch out for his Perilous/Red Kanji attacks, as these act as good openings to get some hits of your own in. One of his Perilous attacks sees him step forward and perform a sweeping kick, but you can simply Step Dodge forward to avoid him and then get a couple of hits in from behind for good meaure.
His only other Perilous attack is a strong thrust kick. When you see him hold his foot in the air for a second and the red kanji appears, perform a Mikiri Counter to cause some significant damage to his Posture and then get a hit or two of your own in as well.
Keep at this and you’ll quickly open him up for the first Deathblow.
The second phase of the fight is identical to the first, but you do need to watch out for his striking attacks that fill your Poison gauge. Step Dodge out of the way of these if possible, but if he does hit you enough times to Poison you then use an Antidote Powder to cure yourself. You need to find a safe time to use your Antidote Powder, and the safest point is probably when you Step Dodge out of the way of the first Perilous attack mentioned above, but if you think you can finish the fight before the Poison effects kill you then do so and cure yourself after.
Keep following the tactics from the first phase and avoiding his Poison attacks and you’ll soon open Lone Shadow Vilehand up for the second, deadly Deathblow.
Killing him will earn you a Lump of Fat Wax, a Prayer Bead, and a wad of experience points.