I've never seen a mangaka drop such a critical story event in an omake. For such a novel series that constantly messes with reader expectations, it makes sense. Brilliant.
So, not so fun fact in pg. 12 Halloween night. Masa recommend Hikaru to be some sort of lantern but really early in web series and early in their relationship Masa managed to upset Hikaru by calling him "Lantern" Multiple times to the point Hikaru ignore him