
I don't think Cain wants to compete with Yahwi for Jooin's heart because he just wanted to see Jooin happy. It will make him feel contented once he know that Jooin is happy even though it means to sacrifice his feelings for jooin. Okay everyone, repeat after me! "CAIN BEST BOY!"
Cain ask jooin if he is happy while Yahwi is the cause of his suffering, tell me why TEAM CAIN like Cain more. ( ̄へ ̄)

Maybe winter was a cat or winter was really a dog and came back as a cat which is mr. Cat now. I think something is up with that friend of him because of how mr. cat reacted to him in their first meeting, the friend is sus so let's kick him out ( ̄へ ̄)
Also mr. cat's hair changed into white just like winter's fur, I don't know anymore. There's a lot of possibilities to consider (︶︿︶)
Cain is like a dog, he's kind towards the person who he thinks that his owner. That's why he's super kind towards Jooin, don't forget that a dog barks and bites those people who wanted or hurted their owner.
"Are you happy?" Every dog wants to see their owner happy but HATED when they're in pain. That's somehow explain Cain's personality, I just compared him to a dog because of some panel where he wags his tail to Jooin ╥﹏╥