Great Serpent Boss Fight
1.Head through The Sunken Temple after getting Gun Fort Key from Kuro
2.Open the door right behind him where you fought the clawed foe.
3.Run across the bridge until the snake busts through the bridge and drops you into the waters below.
4.Follow the leftmost wall and swim fast into the cave.
5.Grab The Riven Cave idol and head back to The Senpou Temple.
After you defeat the Folding Screen Monkeys and receive the Mortal Blade, you should have access to a new Ninjutsu: Puppeteer. Equip this and travel to the Senpou Temple way-point. Right outside, you will see a kite in the air and a rat sitting beside.
Head behind the rat and deathblow him. As soon as you begin the animation to execute a deathblow, another opportunity to deathblow will be available. Once you do this, you will trigger the Ninjutsu and this boy will fly the kite for you with out any demands!
Just chill at the idol and re-spawn.
After you have let him raise the kite, travel up into monk territory. Grapple onto that building at the end and jump through the window where the three monks are praying. Once you reach upto here, you should see a large tree. Start climbing it.
It’ll whip and carry you over to a small ledge. Just beneath you, will be a a few tree branches that you can grapple to.But be measured an careful as you will be swinging past them and not sticking to the branch itself!
Hence forth the path is straight forward. Follow it into the small cave and out to the other side of the cave. You should see tonnes of snow and a small beam protruding out. Shimmy your way out the beam and you shall see the Great Serpent right below!
Target the snake and leap right down on it .Once indicated deathblow it and then you would have defeated THE GREAT SERPENT BOSS!
WATCH IT HERE: