There are a lot of bosses in Sekiro: Shadows Die Twice, but the only one that you have to fight in the water is another Headless. Unlike the previous Headless boss fight, this foe trades slowing effects for some ranged attacks. While it might seem frightening to battle in a moat, the Underwater Headless is comically easy. Here’s a breakdown of how to beat this one phase boss and earn some Ungo’s Spiritfall.
Before you begin the battle we suggest taking some Ako’s Sugar to boost your attack damage. Now dive into the water and dash towards the Headless with B (Xbox One) / Circle (PS4). You can typically land 4-6 blows before the monster counter attacks. Its swings are pretty slow, so if you watch its arms you can typically underwater dash before it hits you.
However, if he does strike you, just swim away and heal. Be careful because the Underwater Headless may fire off a projectile at the player, but if you keep your distance this can be easily dodged. Remember, this monster still does Terror damage so bring either the Terror-specific Gourd or some Pacifying Agents.
Make sure to keep moving around the monster to ensure its ranged abilities don’t hit you. The easiest strategy for this fight is to dash in, land 4-5 strikes and then swim away before it can retaliate. You can actually tank the Headless’ first blow and survive if you’re diligent about getting Prayer Beads. This means you can swim in, attack until he hits you, swim away to heal, and then repeat these steps until the monster dies.
Don’t worry about coming up for air, Sekiro doesn’t force you to keep surfacing. Just lock onto the boss and focus on striking after it whiffs those big wind-up slashes. This should be an easy fight, so don’t panic if he manages to strike you.