Seija and Shinmyoumaru: Shared affiliation through Sanae-induced psychological trauma.

why is this not in the pool #8369 ?
it was there before, why did it get removed?

Because it's not a part of the series according to pixiv, more like a side-scene.

It could be an author's typo, but written as it is, the commentary looks like a pun on verbs "to go" and "to pass away". Please, feel free to edit the commentary if you have a better fitting translation.

just speculation...do you think that the one in Sanae's sack is Kogasa's human form?

gosh...what kind of nightmare she'll inflict to that poor umbrella.