Cain's Links
Rather rocky friendship. Cain tolerates Cas.
Cain is the object of Cas's affection. Cas isn't IN love with Cain. But he is the only Griffolk Cas cares to associate with and be genuine around. Cain is the only griffolk Cas would ever entertain being in a romantic relationship with (note: it will never happen, both because Cain isn't interested, and Cas being aromantic).
Cain cares very deeply about Otto and is constantly concerned for Otto's well being. He's at this point their adoptive father.
The embodiment of the "You are my dad. Boogie Woogie" Vine
Cain tries to keep out of Trench's way generally. He is unaware of Trench's identity as a shapechanger nor as a Griffolk-eater.
Trench enjoys making Cain miserable and keeping him a social outcast. With Cain becoming Otto's surrogate father, this sick fascination of Trench's has become even more pronounced.