The roach oni appears to be an insectoid creature with six legs, long antennae and a tail. An eye is also present the creature's back, which opens when it appears. Although it usually moves around slowly, if Hiroshi gets too close it will sprint at him, killing him.
It first appears on the third floor of the annex in the room where the player obtains the plank, after which it appears in multiple rooms throughout the annex; whether there are many or just one is unknown.
- If the player waits by the door when the roach oni attacks, it can be narrowly escaped.