A wanderer traveling across the country in order to find the 'girl in the sky', a goal each generation of his family has passed on for a thousand years. Yukito lives off his trade, a special form of stringless puppeteering that was taught to him by his mother before she died.
Bishōnen: He looks a lot less generic than most harem leads — though AIR isn't really a harem show in the traditional sense — and even sparkles in the movie.
Deadpan Snarker: In true Key tradition. He complains about everything from dorky outfits to lack of money, all with a hanging aura of "what is my life".
Refusal of the Call: When he first realizes that Misuzu is Kanna's reincarnation, like the girl his mother found and couldn't save, he tries to leave her so she can recover because he knows that making bonds with people will hurt her. He later changes his mind, and then calls Haruko out for the exact same thing.
Street Performer: He tries to make a living as a street performer by making his doll do tricks.
A Threesome Is Hot: Does not actually occur, but his mind does wander to thoughts of a three-way with Misuzu and Haruko, and also one with Kano and Hijiri. Thank you, special CGs.
The first of the three girls that meets Yukito Kunisaki. She becomes friends with Yukito and invites him to stay over at her house. She is a cheerful, slightly clumsy girl, and often mentions the pseudo-dinosauric phrase "Gao" whenever she feels troubled or is about to cry. Since a young age, Misuzu has had a great love of dinosaurs. She suffers from a mysterious illness that makes her ill whenever she comes to love someone and is loved back.
Lethal Chef: "WAH! A cicada came out of the ventilator! WAH! The soy sauce container fell! WAH! The salad oil spilled! WAH! Yukito-san's bacon and eggs have become something beyond imagination! A-wah-aah..."
Rapunzel Hair: It's down to her waist at least, and possibly even lower.
Reincarnation: Of Kanna. They look nothing alike though, unlike many examples of the trope, like Yukito does to Ryuuya. Granted, Misuzu isn't blood related to Kanna, like Yukito is to Ryuuya. Also, it's implied that, thanks to this trope, she might wind up with a happy ending after all, albeit not in her current form.
Stepford Smiler: To some extent. She acts cheerful, but she's really suffering from a generations-old curse which makes it difficult, even nigh impossible, for her to have close friendships with anyone. After all, whenever she does, unless she distances herself, she essentially is condemned to progressively suffer until her life snuffs out.
The younger sister of Hijiri Kirishima. Kano is a wily and energetic girl with a cute side, and is always seen with her small dog, Potato. Like Misuzu, Kano has a curse related to the past.
All of the Other Reindeer: Kano has been teased a lot for wearing a bandanna around her wrist 24/7, talking to animals more than to humans, passing out in class, and just plain being weird.
Conveniently an Orphan: Her mother was an Ill Girl her whole life and died after complications following Kano's birth, and her father, the previous Dr. Kirishima before Hijiri followed in his path, worked himself to death.
Demoted to Extra: Literally in the movie. Kano is widely known as the Least Popular Key Haremette despite having her own small fanbase (which calls her Kano-rin).
Deus Sex Machina: Kano believes that losing her virginity will give her magical powers, thanks to taking Hijiri's effort to rein in Shirahocompletely the wrong way.
The Gadfly: She's a bit of a troll. Before Yuri came along, Kano was Key's main female example despite nearly every male lead being this.
Iconic Item: Her bandanna, which she keeps on her person at all times. In her arc in the game, she gives it away, and in the anime, she takes it off and it blows away in the wind.
A top student in the school, Minagi is very quiet and shy. Though she does not hold a spirit from the past like Misuzu or Kano, she is still rather isolated from others. Until she met Yukito, her only friend was Michiru.
Club President: Of the Astronomy Club, though she is also the only member.
The town doctor and Kano Kirishima's sister and guardian.
Agent Scully: Hijiri believes that she can't believe in magic or she'd undermine her credibility and reliability as a doctor. She doesn't bring up the subject in front of Kano because she cares more about her sister than the fact that they disagree on this point and it was Hijiri who made Kano's belief in magic so central to her character anyway.
My Sister Is Off-Limits!: With good reason. She knows full well how Kano took her words, and should Kano really attempt to "become an adult" and remove her bandanna, which scientifically-minded Hijiri put on her to trigger her back to her normal self, her "illness" (possession) may actually kill her, as far as Hijiri theorizes. She gets better by the end, where it's no longer an issue.
An energetic young girl who doesn't seem to have a place to live. Having befriended Minagi at an early age, Michiru doesn't seem to have any other friends. She plays an important role in Minagi's storyline. She enjoys playfully attacking Yukito Kunisaki and has a fondness for bubbles.
The Reveal: Michiru is actually a wandering spirit who decided to help a lonely girl on Earth after seeing the trapped Winged Maiden. She became a physical manifestation of Minagi's unborn sister to help her through her troubles.
Token Mini-Moe: Not entirely, as she has no route of her own, but she's important enough to the story that she nearly fits the role (unlike, say, Saika).
One of the last winged beings in history. Kanna was deified out of fear for the awesome power inherent in all of her kind, so from birth, Kanna had been kept in isolated areas away from the general populace. Not long after meeting Ryuuya and Uraha, she escaped with them in order to find her mother. As she traveled with her guardians, Kanna began to develop feelings for Ryuuya, and when the party became surrounded by guards, she took to the sky as a diversion after surrounding Ryuuya and Uraha with a protective shield. While in the air, Buddhist monks cast a spell that bound her into a cycle of eternal reincarnation and suffering that Ryuuya fought to break with Uraha, leaving it up to his descendants to find a way to free Kanna.
Godiva Hair: Her hair covers her naked body whenever she strips.
Heroic Sacrifice: When she, Ryuuya and became surrounded by guards, she took to the sky as a diversion after surrounding Ryuuya and Uraha with a protective shield. While in the air, Buddhist monks cast a spell that bound her into a cycle of eternal reincarnation and suffering that Ryuuya fought to break with Uraha, leaving it up to his descendants to find a way to free Kanna, a cycle which culminated in his descendant, Yukito, and the girl, Misuzu.
A skilled, yet low-ranked samurai in charge of Kanna's protection. Unfortunately, after creating a diversion for Ryuuya and Uraha, Kanna was cursed by Buddhist monks to live an endless cycle of reincarnation, suffering, and death. Ryuuya dedicated the remainder of his life to finding a way to lift the curse, and though he never did, he had a child with Uraha in the hopes that their kin would eventually find a way to break the curse. He also received a premonition from Uraha that he was fated to die within the same year as Kanna.
The Gadfly: He and Uraha love nothing more than teasing Kanna.
Someone to Remember Him By: An interesting variant. With Kanna gone and Ryuuya soon to follow her into death, Uraha asks him up front to conceive a child with her for this reason - both to pass on their memories and will to save Kanna on to their offspring, and so she'll be left with their child instead of alone after losing both Ryuuya and Kanna.