Proposing some relationships:

Rain has a massive crush on Issac, who has bested her in an extra-cirricular fight when she was bullying a first-year after classes. Generally she disregards fourth-years as unmotivated ('senior syndrome'), but she likes Issac's easy smile...and hot abs.

Rain [i]despises[/i] Aelin, primarily because both of them talk to forest animals, and he was quick to expose that that was her [i]only[/i] 'druidic' talent. Also, he's an actual noble while she's just pretending, which makes her extremely hateful. Unfortunately for Aelin, she's a teacher's assistant in his combat classes, and she takes every opportunity to hit him a little too hard and a little too often. 

Rain is actually pretty decent friends with Ar'kar, who is in the same class with Aelin. That's because she's stronger than he is, and they both know it, and he hates it, which makes her happy to rub elbows with him.

Rain had Gamil as a teacher, and likes to hang out with him and challenge other students to drinking contests. 

Rain has a lot of respect for Vladimir, primarily because he can kick her ass seven ways from Sunday despite being less strong and not even particularly quicker -- he's just that much better at straight-up fighting than she is. The various magic teachers, she could care less about, but Gamil and Vladimir she'll heed even if they're not directly the authorities in a given situation.

If anyone would like to argue any of that, feel free.