So I noticed a lot of the chapter titles are missing. I thought I'd fix that, but it seems I can't edit them in myself. Maybe a moderator could do it? For now, I just wanted to post them somewhere.

Volume 4

16. That Which is in Motion, That Which is Set in Motion 動くモノ・動かすモノ
17. That Which Must be Protected 守らなければいけないモノ
18. That Which Dispells the Curse 呪いを解くモノ
19. That Which I Really Wanted to Protect 本当に守りたかったモノ
20. That Which Was Retrieved 取り戻したモノ

Volume 5

21. That Which Fell Ill 患ったモノ
22. That Which Risks Their Life 命がけのモノ
23. That Which Must Be Defeated 倒すべきモノ
24. That Which is Frank 打ち明けられるモノ
25. That Which Is Labelled レッテルを貼られたモノ
26. That Which Would Not Be Redundant カブらないモノ
27. That Which Continues to Avert the Eyes 目を逸らし続けたモノ

For volume 5, it's worth noting that the chapters were rearranged for the tankoubon release. If we were to continue using the magazine's serialization order as we are now, then the title for chapter 22 (which was already posted) is misplaced. The order should look like this.

21. That Which Fell Ill 患ったモノ
22. That Which is Frank 打ち明けられるモノ
23. That Which Is Labelled レッテルを貼られたモノ
24. That Which Would Not Be Redundant カブらないモノ
25. That Which Risks Their Life 命がけのモノ
26. That Which Must Be Defeated 倒すべきモノ
27. That Which Continues to Avert the Eyes 目を逸らし続けたモノ

BTW, you'll notice I used a constant term for the titles, much as they have in the Japanese version. I realize that in English, we tend to differentiate people and objects. However, "that which" seems like it could work universally to some degree, at least so far as I recall its usage. Though, if anyone has any better suggestions, feel free to mention it. But whatever's decided on, I would recommend going back and editing the previous titles as such.