Kagerou/WMG

Cho's mother was human.
She died of "the age", according to her half-sister, and it would explain why she likes humans so much.

You know what, this is gonna be long. Regarding that mind-screw scene with Nadia's silhouette... emitting dragonflies...
Word of God says that the red handprint represents sexual abuse. The comic has a history of having something happen in Kano's head with the eventual results - in reality and in his head - not shown for another few (dozen?) chapters. Dark is Kano's unresolved issues over Nadia, repressed to hell and therefore manifest as two separate personalities in Kid and Red. Dragonflies are symbolic of Fuuka/Tonbo/Tcaolin/Whatever Princess Lady. The dragonfly-guts show Fuuka having helped bring about some kind of catharsis, and the (probably) utter destruction of Red means that Orbkiller's zone and all her dead girls, being vindicated, serve no purpose. (Orbkiller wanting to finish her cigarette before she 'dies.')

Red killed Heyoka.
The story is Tarantino'd between the real world and Gray World. The bloody grate and soda can both seem to be related to Heyoka's murder at the hands of... someone. Despite being in denial, Kano seems to know, from circumstantial evidence, that he did it, but he's not yet aware of Red's existence in the real world. Kano is indifferent to Heyoka's gender-bending but Red... wouldn't be.

Killing Heyoka is what prompted Kano to try cutting his right hand off.
Kano's finger scars don't seem to exist yet in the Real World.