The following guide will walk you through The Source of Evil mission in Nioh and prepare you for the Gasha-Dokuro boss in the end.
Nioh The Source of Evil
The mission starts right after a cutscene unveils Gasha-Dokuro. Take the immediate right and deal with the skeletal warriors. Move towards the left to find Tenkai by a structure. Upon talking to Tenkai, you’ll get the Soul-Soothing Comb that you require to defeat the Gasha-Dokuro boss.
How to Find the Shrine?
Make your way across the ramp. While passing through, a bunch of dangerous enemies will spawn in the red circular areas very similar to the Revenants. Be aware of them while progressing through.
On the right from here is the area where you’ll face the Gasha-Dokuro boss. Before messing with the boss, you’ll come across several red crystal clusters in the area. Interact with the first one to drive a sike through to neutralize it.
From this cluster, run past the battlefield to a structure ahead. There’s no need to bother yourself with the Yokai there which are in huge numbers there. Just run past them and head ahead.
Take a right from the house and there’ll be a small tower with a fallen log in near proximity. Get on the log and on the path to the right is a shrine. From there, make your way back to the boss.
How to Defeat Gasha-Dokuro
Before taking down the boss, make sure to purify the Red Swirls of Yokai Pollution. This will serve the great purpose of making it easy to deal with the boss. They can be purified by stabbing them with the Soul Soothing Comb that you’ve got.
They are three in total and purifying them will shift the momentum from Gasha-Dokuro to you by stopping from them sapping your Ki and giving you three buffs for standing in the purified swirls.
After doing so, jump in to fight the boss. The hands and feet of the boss are its weak spots and hitting crystals upon them make it stumble and lure his head open for devasting blows. Start attacking one of his legs and once the HP of the leg reaches a minimum, you’ll get a shoot time to reach the highest ledges.
At this point, the boss’s head will be open for attacks. Make maximum use of the buffs and living weapons to your advantage as the head won’t be down for a while. Do the same to its other leg and lure his head open for attacks.
Get on the second ledger to attack its hands. Do the same to the hands as you did to the legs. Then take down his head and try to deal the maximum amount of damage. This potentially kills the Gasha-Dokuro but in case it is still left with some HP, attack the stomach to get rid of the boss.