Is there a tag or pool that describe a ghost/ethereal-being that is scared of other ghost/ethereal-being?
There's one specific to Youmu.
In any case, Kogasa isn't a ghost or ethereal being, she's a tsukumogami. She's an object inhabited by a minor "god". She has a physical body, but she was never alive until she became animated. Murasa is an actual ghost, a dead girl who once lived, but drowned, and is now sinking ships at sea.
For others, there's the irony tag. Doesn't really apply to Kogasa, because she's not a ghost, and is something of a coward in general anyway.
Youmu has a pool because her irrational fear of ghosts and scary things is a recurring meme. Additionally, not all cases of this would count as irony, and not all irony cases are of her being scared of ghosts.
Though I could somewhat see what you mean, I'm not sure when you say irony doesn't apply to Kogasa, her schtick is her ability/habit to scare people, and yet she scared shitless by Murasa.
If anything else, thanks for the answer I'm just curious if there is pool or tag that isn't limited to certain character, that I have described before.
They usually use the term "Surprise" for that. Searching for the two tags tatara_kogasa scared barely brings up 4 pages worth, where she's not always the one being scared. tatara_kogasa surprised nets you 20 pages, but that's mainly courtesy of mizuki hitoshi's ongoing 4koma series.
