When is comes to siblings, the younger sibling, will often times try to mimic the behaviours of the older sibling, while also trying to surpass them, which would explain why Volks is a lot better at letting his love interest live their own life then Cole. Cole is a yandere, which yandere's are protective and possessive of their love interest to the extreme. Things are less awful when you're around. Volks is some what possessive of MC (the protagonist), we can draw the conclusion from one of his lines, 'Hey. Physical similarites doesn't make them siblings, but we have other evidence to support our theory. Volks could have his eye color from their mom, while Cole could have his eye color from their dad). now for physical evidence, they have roughly the same build and skin tone, they both have the same hair color, and while they don't have the same eye color, they could have gotten them from different parents (ex. Their ages and birthdays would make it possible for them to have the same mother, because Volks is 22 and born in Feburary, while Cole is 20 and born in November, they have at least (obviously) nine months between their birthdays.

First off, they're the non-visual evidence, both of their blood types are A-, and they are roughly the same height. We came to those conclusions by looking at the similarities between the two. My friend and I believe Cole and Volks are brothers, or at the very least related.

Blush blush nsfw