This is the first mini-boss you’ll encounter past the first sculptor’s idol in Ashina Outskirts (Gate Path). Since he’s encountered quite early in the game, most players may die several times due to the sudden difficulty spike of the battle. To make it easier for you, you have to perform a stealth deathblow on him. You can do this by grappling to roof of the gate in front of the idol then using the cliff on the left to approach him from behind.
How to defeat this boss?
There are no other enemies in the area he’s in so you only need to worry about his line of sight. Follow the path indicated below to successfully sneak behind him and perform a deathblow.
During the battle, make sure you lock on to him so you can keep an eye on his movements. His sword has wide and long reach so be careful not to misjudge your evasion distance from him. His attacks are slow and you can find a lot of openings. Be careful of his unblockable side sweep; if you jump at the right time, you can step on his head and get a free overhead strike. Otherwise, hold circle to increase the distance of your evasion.
One cheap tactic against him is evading his attacks then performing a single lunge (charged attack) after he performs his perilous (red warning) attack, his slow overhead slash, and his basic two-slash combos. You can interrupt some of his normal attacks by using quick slashes in between but you have to be prepared to parry/block quickly.
Don’t be greedy
This mindset is universally prevalent across most of the bosses you’ll face. Don’t be too greedy with your attacks or you’ll leave yourself open. If you get the chance to counterattack, landing 2-3 quick slashes is mostly enough, or one powerful lunge. Combat against bosses in Sekiro requires a good balance of patient defense and offense. Block/parry/evade first, before counterattacking. Exploiting the opportunity to use a tool or attack is essential for winning difficult boss combats.
When his posture damage starts to increase, he will perform a posture recovery (white aura) move to recover his posture gauge. His vitality will remain the same, however. Keep whittling down his HP while remaining on a defensive. Once you deplete his HP, he’ll be open for a final deathblow.