Tavros likes Karkat. He's always kind of liked Karkat!! . . . Minus the bad feelings his first memory gave him because his very first memory was STOP PLAYING GAMES FOR GIRLS YOU ASSHOLE after the cliff incident. Later memories proved that while Karkat was grumpy he really wasn't a bad guy so he got rid of those bad thoughts due to that. :|a Karkat is probably one of his closer friends in Aather really, and there is a lot of trust there. Also, he knows they are the last of twelve trolls so THERE IS SOMETHING that only happens when you're the last of your species.

Also Marine . . . doesn't intensely like Karkat, but she doesn't dislike him either even if his view on the impossible is completely different from hers, since her viewpoint comes from a show that slammed together Gurren Lagann and Sailor Moon. I wouldn't say she's neutral on him or anything, buuuut he's ... there. He honestly benefits from the fact that arguing is a sign of affection with Heliodor.

Reverse for both?