The character sheet for Arcaea.
- Art Evolution: When a character is awakened, you unlock flashier/more stylized art of them, sometimes with a new outfit.
- Costume Evolution: Hikari and Tairitsu's outfits change over the course of the story, while Lethe's dress and scythe get a whole new look in her awakened art.
- In addition, the CHUNITHM partners get new outfits upon awakening.
- Identity Amnesia: Every character who wakes up in the world of Arcaea has no memory of who they are, including their name.
- Meaningful Name: Most characters' names have a meaning that relates to their story/overall theme.
- Hikari means light.
- Tairitsu means conflict, referring to her eventual conflict against Hikari when they meet in the Adverse Prelude story.
- Kou means crimson, referring to her song pack (Crimson Solace) and her outfit color.
- Shirabe means melody, and she carries a musical instrument (more specifically, a guitar) with her.
The Hero Protagonist of the main story. A girl who first wakes up surrounded by light Arcaea. Enjoying the sweet memories the Arcaea has to offer, she begins to collect them for fun, without questioning the existence of the world or herself.
- To Tairitsu.
- Also to Saya. When Hikari first wakes up, she naively accepts the existence of the arcaea, and does not suspect or question her own identity. In contrast, Saya questions everything upon her awakening, and stops at nothing in order to find out what created the arcaea, as well as the world they currently inhabit.
- Nice Hat: Wears a beret with most of her outfits.
- Quest for Identity: Embarks on one after breaking free from the cage of light Arcaea.
The Villain Protagonist of the main story. A girl who first wakes up in a ruined tower, surrounded by dark Arcaea. Disgusted by the negative memories within the Arcaea, she makes it her mission to collect all of them and destroy them permanently.
- Dark Is Not Evil: Initially played straight in the Eternal Core story, in which she vows to purge all of the negative Arcaea to rid the world of misery. Eventually inverted during the events of the Vicious Labyrinth story and discussed in the Black Fate story.
- Elegant Gothic Lolita: Her main outfit style. Paired with a Parasol of Prettiness in her Grievous Lady and Tempest outfit.
- Never Bareheaded: Always has two bows in her hair.
- Omnicidal Maniac: What she becomes during the Black Fate story. After realizing that there was no point in destroying the dark arcaea, she decides to destroy the entire world, taking herself and Hikari with it.
- Parasol of Pain: Along with the negative Arcaea she has accumulated, she uses her parasol as a weapon to kill Hikari in the Black Fate story.
A cheerful girl who, ever since waking up in the world of arcaea, has been living under an Endless Daytime.
- Girls Love Stuffed Animals: Carries a teddy bear with her.
- Hand-Hiding Sleeves: Specifically, Cute Sleeves in her awakened art.
- Pink Means Feminine: Has pink hair, a teddy bear with pink ears, is depicted on a swing with light pink flowers in her awakened art, and her song backgrounds are all pink too.
- You Gotta Have Blue Hair: Has waist-length pink hair.
A girl with foggy memories of a past life.
- Art Shift: Unlike the other main/side story characters, whose art was drawn by cierra, Lethes illustrator is softmode.
- Horned Humanoid: The only character in Arcaea who has horns.
- Interface Screw: Her Awakened Skill is described as "sense of incompleteness". In other words, it hides several gameplay interface elements like the score and combo counter.
- Sinister Scythe: Carries one around.
An inquisitive girl who is able to assimilate the memories of the arcaea and inhabit them, reenacting the events that occurred within said memories. Her sole goal is to understand everything about the world of arcaea, from the memories that inhabit it to the world's origin.
She was released with the Absolute Reason song pack, and was the first side story partner to have a written story on release.
- Boring, but Practical: She tops out at 90 Step and while it's still lower than that of many other Partners, she does have the highest Step stat of any Partner who doesn't have a Hard gauge, allowing for reasonable risk-free grinding if one wishes to play charts that they are not sure they can Hard clear.
- Early-Bird Cameo: Appeared in the cover art for Alexandrite before she was officially released as a partner with the Absolute Reason song pack.
- Exact Words: Her Skill is described as increasing the amount of Recollection Rate change per note, except for Far notes which do not increase or decrease the gauge. While getting a Pure will now give you twice as much gauge gain, the unexpected part of her skill is that a Lost will cause three times as much damage. After all, the skill description never stated that it only applies to positive gauge change.
- Fashionable Asymmetry: Has a flower in her right eye, and only wears a stocking on her right leg.
- Foil: To Hikari. When Saya first wakes up, she questions everything upon her awakening, and stops at nothing in order to find out what created the arcaea, as well as the world they currently inhabit. In contrast, Hikari naively accepts the existence of the arcaea after waking up, and does not suspect or question her own identity.
- Slashed Throat: She slashes Donovan's throat to provoke him into reacting, but her surroundings shatter and dissipate before she is able to get one.
- You Gotta Have Blue Hair: Has seafoam green hair.
Tropes applicable to both:
- Interface Screw: Their Skill, in addition to mirroring the chart, also hides Far judgments including whether they were early or late hits. (Early/Late for slightly-off Pures are still shown, however.)
Tropes exclusive to Alice:
Tropes exclusive to Tenniel:
- The One Guy: He's the game's first and only male partner. Granted, there have been male characters in the story in the past, Donovan from Absolute Reason in particular, but Tenniel is playable, has a portrait, and is a main character.