Nightfall Chapter 3 can't find all enemies

[fondenteblack]

Hello, i have to get the oni medal in this chapter, i completed it 2 times but somehow i'm missing enemies. is there a secret area of hidden enemy i'm not aware about? this is so frustrating. I got all katanas with no problem, so i thought i explored well enough to kill everybody, but no.
EVERY video on youtube is ghost/no kills, so it doesn't help.

[fondenteblack]

Did the mission for the third time, killed the same number of enemies (81), this time i got the oni medal. I don't know how but i don't care anymore.

[Aryn Finngard]

What I did for every level before continuing is walking through the map carefully and whistling to draw attention to me.