Nurikabe is a door-like creature that blocks the way to hidden places. On this page of the NiOh 2 guide, you will learn how to deal with this enemy.
Nurikabe can be found thanks to careful exploration. If a particular wall has two holes of similar size, located at the same height, then you can assume that you are dealing with a hidden passage. To confirm your suspicions, approach the wall - eyes appearing in the hole mean that this is a secret passage.
There are two ways to open it. The first is combat - when you attack Nurikabe, it will immediately fight back and reveal the passage. If you chose violent approach, watch out for its area attacks and boulder throws.
Using gestures is a much safer solution. The eyes of a Yokai glow with a certain color - blue, yellow, or red. To make Nurikabe let you pass without killing it, you must make a gesture marked with the same color.