The Lunar Capital has been (or is currently being) invaded by the variants.
The existence of Variant Ringo, Variant Seiran, Variant Reisen, Variant Reisen II, and Variant Kaguya in the story should be a red flag that something bad is happening on the moon.
Variant Marisa having a magical paper fan similar to the one Toyohime uses to threat Yukari in Silent Sinner in Blue manga is another red flag.
Yuuka and Wriggle are very close, and probably in a relationship.
In Rumia arc, Wriggle claims that Yuuka is very kind, unlike what most rumors say about her. The same arc also has Wriggle saying that she wants to give Yuuka a present.
When Yuuka sees Wriggle's mutilated corpse, she shows a grieving expression (though Yuuka hides it pretty well) and quietly gives Wriggle burial, which implies the closeness betwern them.
Related to above WMG, Medicine Melancoly is Wriggle's wingwoman.
Notice that Medicine is close to both Yuuka and Wriggle to certain extent but shows no romantic interest on either. It could also mean that Medicine is too young to be in love, though.
