In Nioh, the Samurai from Sawayama quest is tough, as it is set in a castle with lots of winding passages and stairs and underground passages that lead here and there and sometimes nowhere. Here is a walkthrough game guide of Sawayama quest on how to get to the boss.

First from the first shrine get to the cyclops monster with the goalie key.

Then get from the first shrine to the second shrine. William will notice a new type of monster set – a skull chamber with lots of skulls around that. Defeat the skull chamber first, before concentrating on the skills. Then head up the spiral staircase; be careful of the large boulder.

Get to the second shrine, and the hero is within reach of the boss the Dark Samurai, as downstairs from the second shrine.

If you are having trouble with defeating the monsters in this area, head to the Master of the Twin Blades side mission to get some NPC companion action and XP.