Ok, so we don’t know that much about Cho, and there are many people who have a lot to say (and many of it not that good) about the few interactions she has with the main characters. And the one that shows her loyalty is probably one of the most criticized .
We got introduced to her in the fourth book, “Harry Potter and the Goblet of Fire”, but back then we didn’t get a lot of information on this part of her character. There is one instance that can be interpreted as her showing loyalty, but I guess it’s not even close to the level shown later in the books. This moment is the one when Harry, after stumbling over his words for a bit, asks her to the Yule Ball. She doesn’t even consider it because she is already commited to someone else, and even though she feels bad for Harry, she is really clear.
But the real moment of truth comes, as we previously said, during the fifth book, “Harry Potter and the Order of the Phoenix”. When the DA is discovered and some of the members are captured, we get to know who was the one to betray them. It turns out to be Marietta Edgecombe, a fellow Ravenclaw. She was at first reluctant to join, but did so to be close to her best friend, Cho Chang. And here comes the part that makes everyone so angry at her. Cho decides to stand with her best friend and defend her, even though that makes her clearly unpopular.
But this is the thing, Marietta IS her best friend, and Cho considers it her duty to empathise with her because she is THAT loyal. It turns out that Marietta’s mother works in the Ministry, close to Umbridge, and Marietta is in a difficult situation. She can talk and protect her mother but be a traitor, or keep silent and put her mother in a terrible position if the DA is ever discovered. We all like to think that we would keep the secret no matter what, but without being in a similar situation we will never know if that’s actually true. And, remember, Cho is Marietta’s friend, and seeing how she reacts makes me believe that loyalty is basic for her. I also have to say that being a teenager and having suffered through major emotional turmoil for quite a while might make her a tiny bit biased against Hermione and what she does. So, put those two things together and, there you go, Cho’s reaction makes sense now, doesn’t it?
Also, remember that all of this means that her ‘relationship’ with Harry is finished for good. I don’t believe that is what she truly wanted or was looking for. However, her loyalty to her friend runs deeper than any other thing, and so it must be commended. I mean, loyalty should be celebrated even if it doesn’t exactly fit our standards. We all know Marietta’s choice was not the best one, but she was between a rock and a hard place, so no option would have been perfect. For Cho, it’s either stand with someone who has probably been her friend for all her school life or choose her new friends. What would you have done?
This is one of her most known traits. She shows a lot of empathy towards everyone around her, and when she suffers, she suffers deeply. This is specially seen after she loses her boyfriend after the Triwizard Tournament at Hogwarts. She feels his loss profoundly and it takes her a lot of time to actually start moving on from that, even though it may seem different. She is even dealing with that during her relationship with Harry Potter, which I believe is one of the main reasons why their love story is doomed from the beginning.
Another situation in which we can see this is when she rejects Harry after he asks her to the Yule Ball. She rejects the offer because she has already committed to going with the other Hogwarts Champion, Cedric Diggory, but she does so nicely and with care. She also refuses to wear the badges Draco Malfoy creates to mock Harry because she doesn’t believe that is a nice thing to do to anyone. So, she again shows empathy and care for those around her without being overly showy about it, which tells us that she is genuine about it.
Next year, while in the DA, she starts her relationship with Harry. It is a complicated one, seeing as Harry was the only witness of her boyfriend Cedric’s death. This means that there are many uncomfortable moments during the length of their relationship. The most memorable one is the kiss under the mistletoe, when she cries while kissing Harry. She may be willing to start a new relationship, but she cannot help but feel confused about it. Which, as I said before, speaks to the depth of her emotions.
Cho is one of those people who, once they make a choice, will not be deterred from her goal, no matter what the risk is.
Joining the DA, for example, shows her inner determination and strength, seeing as her mother asks her directly not to cause any trouble at school to avoid putting her job on the line. But she just can’t forget that the Ministry lied about Cedric’s death and Voldemort’s return. She feels that she has to do something about it. And when she finds about the idea of forming a Defence Club, she is 100% willing to be there, no matter the consequences.
She also is there at the Battle of Hogwarts with the rest of the DA. Even if she hasn’t ended in good terms with Harry and the rest, she still thinks her place is fighting against Voldemort with the DA. And there she goes, without a doubt. She is completely determined to be there for the fight with everyone else, and help as much as she can.