wait a sec, somehow the ( wheat? ) field where shroomhead and egghead walk together.. seems kinda like the same setting where Chito and Yuuri ends up after.
Yeah, that is likely not just a coincidence. if you look at the cover page of the first chapter of this manga you can see two girls that look very much so like Chito and Yuuri sitting together on a bench off in the distance amidst the wheat. Also, if you check out what amounts to the prequel to this series it heavily implies that the world we are seeing in this manga is some sort of purgatory or afterlife. Notice when the older sister goes out fishing in the field, she corrects herself and says rather than actual fish she is trying to capture the soul's of fish.