Hybrid Discrimination: After the darklings leave him not quite human in Touching Darkness, both they and the ancient mindcasters in Madeleine's head react to him with disgust.
Jerkass: Sometimes in general, often when struggling with his darkling side.
Large and in Charge: Rex is rather tall, but doesn't make much use of his size due to being bullied and abused most of his life. This changes in Blue Noon, when his darkling half makes him more aggressive, as well as physically warping his body at the worst of times.
Meaningful Name: Rex means king, and Rex is the leader of the midnighters. Madeleine intentionally created/recruited the other midnighters to rebuild Bixby's midnighter community for Rex to 'rule.'
Missing Mom: Mrs. Greene sells cosmetics for Mary Kay and only drops in on his life occassionally. She doesn't make an appearance that we get to see, but her pink convertible does.
Bad Powers, Good People: She turns out to be this (relatively speaking) in Blue Noon, when it's revealed that mindcasters put all of the midnighters in town under mind control and made them think that they were better than the daylighters and had them oppress them. Even the Darklings didn't like them. While Melissa does use her power to her own gain every now and then she has higher standards than that.
Byronic Hero: Melissa's powers are so painful and invasive that Jonathan suggests she has a literal death wish. Everyone who touches her (therefore gaining access to her thoughts) pities her, much to her chagrin.
Instant Expert: Subverted. It seems like Melissa immediately fixes all of her problems with mindcasting when Madeleine shares her memories at the end of Touching Darkness, but she actually just gets the tools to be functional and continues to develop her powers over the course of the last book.
Power High: Jessica loves the feeling she gets when she uses her flashlight in the blue time as she can feel the power of the daylight world pouring through her body and out of the flashlight. The same goes when she sticks her arm into the time frozen lightning bolt and she can feel the waves of energy rolling into her and jumping out at her enemies.
Required Secondary Powers: All of the other midnighters are extremely sensitive to bright light, because their eyes are built for the secret hour. Jessica's eyes are reversed in the fact that her eyes don't flash purple like the other midnighters and her eyes feel tired after being in the blue time for awhile and she gets a headache after trying to read a book in the blue time and looking into the dark moon. However, she is the only midnighter who can tolerate bright light and wouldn't benefit from wearing dark sunglasses during daytime. When she first uses her flashlight in the blue time, her eyes feel much better and not as tired as usual while the other midnighters scream in pain and have to cover their eyes. It makes sense, as it would be pointless to have the power to use bright light during the blue time if you can't even look to see where you are aiming it. The same could be said of the lightning in her hand trapping her in midnight. If she crossed over into regular time, where her power doesn't work. The lightning would fry her body.
Swiss Army Power: Jessica can use her power with matches, torches, bonfires, flashlights, flamethrowers, candles, fireworks, sparklers, all of the lights in an entire office building, and even lightning.
Bad Powers, Bad People: Due to her upbringing she has been tainted by some of the unsavory beliefs of the old mindcasters.
Chekhov's Gunman: She first appears in a cameo in The Secret Hour, when she chases Jessica off of her lawn.
Evil Counterpart: She is kind of one to Dess as they are both extremely smart and sassy. Also in a similar way to how Madeline misses the days when the mindcasters controlled everything, Dess cannot wait for the day that she will have a group of polymaths to lead. While Madeline has already learned almost everything about midnight and takes pride in her knowledge,Dess wants to discover as much as she can about midnight and takes pride in her discoveries such as Dessometrics.
Evil Mentor: To the whole group, but particularly Melissa and Rex.