Asen's Links
Asen was scared at first, when everybody died except them and Californio, but it turns out CF didn't know what was going on either. Moreover, CF didn't care about Asen's appearance, which was great. CF has never been judgemental towards them, which made Asen get attached to him. They use him as a shield a lot of the time, and aren't afraid of admiting they rely on him, but there's a point where they dislike depending on him for everything.
CF is probably the person who has it easiest to embarrass and fluster Asen. It's possible that Asen develops feelings for CF, but it really is very confusing.
Asen is CF's favorite person. Even if they're easily irritated and snap at him every now and then (which isn't enjoyable), CF is very fond of them. He wants to protect them, he doesn't want them to get hurt. He doesn't like seeing them in pain. He doesn't even understand why he wants to see them be happy, but he doesn't care for explanations like that.
While they might bicker every now and then, CF really is loyal to them.
Ceena is the person who accomplishes that Asen starts realizing they are capable of feeling friendship towards others and not wanting to wipe humanity out of the planet. Asen cares about her! She embarrasses them sometimes but at the end of the day they don't mind, and with time they will realize Ceena is somehow the family they probably needed.
She cares about Asen the same way she cares about everyone who might be her friends, she's just naturally like that! But she could sense from the beginning that Asen was troubled and sad and Ceena wasn't able to not do anything about it. She tries to engage in many activities so Asen will feel better, and sometimes it doesn't work, but sometimes it does! And she discovers Asen is actually a really nice person to talk to, they've had it rough so far is all, and that's what friends are here for!
Asen and Cseren's personalities are somewhat similar. It means they can agree in some things, but Asen is more estranged from society than Cseren so it's not like they completely understand each other. Cseren doesn't anger Asen, but they don't pay attention to him too much.
Nonetheless, since they know Cseren and most people in their city have features similar to Asen, they've been less hostile. It's not like Cseren is as talkative as Ceena, though.
Cseren doesn't make a lot of effort to maintain a relationship wtih Asen, but he doesn't hate them or anything like that. If anything, they look pretty normal to him, which is weird for Asen. There's a lot of social cues that Cseren gets and gives and doesn't realize Asen doesn't.