As for how I save it after he is in goblin camp.

1. I played chicken-chase and with huge bet
2. After she-goblin tried to scam me I used some kind of talk to give me back mine money
3. Talk to the Owlbear (I got speak with Animals spell) and Ask him to join you. He says about goblins
4. Once again talk to she-goblin and tell her you taking Owlbear with you. Little cup will just run but dont sorry
5. During nightcamp (sometimes you need sleep 2-3 times because only one camp event is per sleep) he will show up. Give him some food but some companions will scare him off. But dont worry.
6. During next night Owlbear cup will just sit on your camp. Talk to him and you will see that it have hurt paw. Heal it. And with that Owlbear Cup will stay with you permanently

I don't know what happened. I literally slaughtered the entire goblin camp just to free the owlbear and he disappeared.

Oh yes. I don't even know I can rescue it. Shame on me ;_;

Thats why you need another playthrough, where you save the cub and get it in your camp :)

I feel bad about it. That was not my intention. :(

Nooooo

well.. i killed it. told him to attack the gobbos.

Mine little fluffy boi

OMG! GIMME!