Primary Characters:
Alisa Reinford - Alisa was most definitely written to be the main love interest, that much is obvious. There's not much to say about it but since they didn't exactly end up a couple during the course of the game makes me think that they are planned to get together further down the timeline. She gets doted on the most by far and for the reason stated above. Pretty straight forward, not much to say.
Laura Arseid - She isn't exactly a "friendly competitor". When it comes to swords, she's deadly serious all the time and love doesn't come into the equation. Think Samurai honor. She was also brought up on the legend of the Lance Maiden and pledging ones self to someone who she deems a worthy figure. She wants to be Rean's sword because she feels that he's the first person she has met which fits that description for her that could use her help. She really likes/loves him, but I don't believe it's to the level of a lifetime love partner as opposed to knight pledging allegiance to their lord.
Emma Millstein - Emma is somewhat bland and there isn't a whole lot to say about her. She's similar to Rean in some ways and is half as troubled by it. She attached herself to Rean mostly because he pushed the right buttons at the right time, mostly thanks to everybody else kept pushing Rean along and he used their advice on her. Their final bonding events together seem a little hollow when you look at it that way and it's rather sad despite the whole exchange of words.
Fie Claussell - Yes, she sees Rean in a similar light as Zephyr's leader in a number of ways. A leading figure who makes decisions and shields their allies as necessary while being very caring towards everyone around him. I'm not entirely convinced this is love in a romantic way as opposed to it being a familial kind of love you would have for an older sibling.
Millium Orion - Millium doesn't really understand the concept of romantic love yet. She's still very much an adolescent child. She's also not really Ouroboros, but was created/born in the Black Workshop. However unlike Altina, she doesn't seem to be on "loan" from there. It's left unknown, but I would guess that she was taken/given or bought as Osborn seems to have some kind of working relationship with the Black Factory. Now I'm not
entirely sure if the Black Workshop is the Thirteen Factories (Ouroboros), just a small part of it or some kind of separate entity that works with them. I know it's mentioned in both Trails in the Sky SC & Cold Steel II. I'm hoping Trails in the Sky the Third will clear up some of this for me. The ending will show that she's capable of emotional growth though.
Sara Valestein - She sees herself as a mentor/older sister to Rean. However sometimes when she teases him, he manages to hit a few suave lines that hit her pretty heavily. Sara refuses to let it get into any kind of relationship beyond student and teacher. She says maybe in the future down the line if he becomes her type of suave guy, but until then she wouldn't let herself go that far. I believe her fixation comes from Cassius Bright (Hard image to live up to) as he was the one who resolved the bombing incident in Heimdallr that she was a part of and part of her reason for becoming a Bracer with the other part being Beatrix. (I
think anyways, some context is provided and exact dialogue details are a little foggy for me)
Sub Characters:
Elise Schwarzer - Yes, essentially she's a bro-con. I'd say it's 50/50 whether or not she would actually pursue anything though. She clearly has feelings for him and wants the best, but I'm not sure she would be able to push herself for it without outside help. She really wants him to be a Schwarzer and to find his own happiness even if it means leaving her. Mostly she steps in because she realizes that Rean is trying to leave due to his own personal guilt and self-doubt.
Sharon Kreuger - She doesn't want Rean at all. She
really enjoys teasing people. This is a common trait of dominatrix, which she
totally is. Ultimately I don't think she really cares if Rean ends up with Alisa or not. Yes, she wants Alisa to be happy, but it doesn't have to be Rean. If Rean did something unforgivable to Alisa, I feel that she would dismember him in a very slow and agonizing way.
Claire Rieveldt - She does't seem to actually want into his pants at all. I feel that after beating the game that she sees herself more as an older sister figure than anything. It's also entirely possible that she could really be his biological sister, however that's just speculation.
Towa Herschel - She was actually a last minute addition to the cast (Essentially a Falcom Mascot creation). You can tell this because she wasn't written into Ao/Zero for when the Crossbell Conference took place over there. She's the dutiful type who's good at everything and seemingly likes people who would closely help and work with her. Due to the whole student council thing, yes they got rather close and she develops feelings for him. However she bottles it up and just acts as a comfort figure. She has no issue throwing aside her feelings to make him happy.
Alfin Reise Arnor - Her teasing is definitely a trait gained from being around her brother, Prince Olivert. However seeing through her and cheering her up when she was down hit her pretty hard. Not to mention the events that took place during the intermission. It started with a curiosity because of Elise, her friend and ends up being a bit of a crush. It's a potential match, but not one Rean would go for because of his own inhibitions. She also understands her position and would never force Rean into any kind of relationship by publicly asking him.
Other Characters:
Rosine - Eh, I don't really see it. At most I could see her thinking of Rean as a friend, potentially good friend and nothing more. Rean does have
some dirty thoughts about her on the other hand though.
Vivi - She is after anybody who can make her laugh and isn't mean to her sister, Linde. She'd be totally fine with Rean but doesn't really seem interested in pursuing any kind of relationship at the moment because she's having too much fun screwing around.
Dorothee - She doesn't want into Rean's pants, but she does want Valimar into his pants. Maybe Jusis, Elliot, Machias or even Patrick too. If she hasn't written a book by the end of Cold Steel II with regards to this, then I'd be shocked.
There are a few "I love you" thrown around in some final character events, however Japan has three versions of "love" that mean different things. Unfortunately English doesn't. While XSeed did great translating it, I do kind of wonder how the final bonding scenes that have that were worded in Japanese.