Kou is one of the Partners in Arcaea. She is unlocked by purchasing the Crimson Solace pack in the "Side Story" section.



Kou's name means "crimson" in Japanese.


Seemingly in reference to both her namesake and the name of her pack, Kou is primarily dressed in shades of red.

She has long, straight, light pink hair and green eyes. In her hair, she wears a burgundy headband that is shaped like a pair of rabbit ears and has gold ornaments at its tips.

Kou wears a long, faded crimson garment with a strapless sweetheart neckline over top of a short burgundy pleated skirt with a white stripe. The center of her top is white with white buttons to the sides; its lower half also has white buttons and stripes and splits below her waist, revealing her skirt. A brighter crimson ribbon is fastened loosely around her waist and decorated with gold ornaments. Kou's sleeves, separate from the rest of her clothing, are crimson with pale pink and white ruffles that extend long enough to cover her hands. She also wears a white collar with a ruffled bib and a burgundy bow, to which more gold ornaments are attached.

Her boots are off-black, have laces, and extend to her thighs; underneath she wears a pair of tights slightly lighter in color.

Kou is always depicted holding a white stuffed bear with light pink ears, hands, and soles. Its eyes are represented by gold ornaments, it has a crimson bow around its neck, and its headband is identical to Kou's. When awakened, the teddy bear is shown holding a cake on a plate.


Kou has been officially described as "a cheery girl with a long history in the world of Arcaea".[1]


The following section of this article contains spoilers. Proceed with caution if you have not read the Story yet.
Divider story

Black Fate

Story blackfate
Divider sidestory

Absolute Reason

Story absolutereason

Story cyaegha

Crimson Solace

Story crimsonsolace

Story gloryroad

Ambivalent Vision

Story ambivalentvision

Story corpssansorganes

Adverse Prelude

Story adverseprelude


Story meeting

Luminous Sky

Story luminoussky

Vicious Labyrinth

Story viciouslabyrinth

Eternal Core

Story eternalcore
Partner 01 Partner 02 Saya-0 Partner 03 Partner 05


Kou can awakened at Level 20 since v2.4.0 by consuming:

  • 25 Crimson Cores.
  • 5 Hollow Cores.

Stats by Level

LEVEL 1 2 3 4 5 6 7 8 9 10
FRAG 60 60 60 60 61 62 63 66 68 72
STEP 47 47 47 47 48 49 50 52 54 57
OVER 25 25 25 25 25 26 27 29 31 34
LEVEL 11 12 13 14 15 16 17 18 19 20
FRAG 77 81 83 86 87 88 89 89 89 90
STEP 60 63 65 67 68 69 69 69 69 70
OVER 37 40 42 44 45 46 47 47 47 47
LEVEL 21 22 23 24 25 26 27 28 29 30
FRAG 91 92 93 94 95 96 97 98 99 100
STEP 71 72 73 74 75 76 77 78 79 80
OVER 48 49 50 51 52 53 54 55 56 57


Kou is mainly focused on the FRAG stat, and is a reverse of Tairitsu (Axium) at Level 20. Notably, she is an exact reverse of Lethe at all levels, even when awakened.

  • Her maximum FRAG stat translates to a 2.00x fragment multiplier.
    • At level 20, her FRAG stat translates to a 1.80x fragment multiplier.
  • Her maximum STEP stat translates to a 1.60x step multiplier.
    • At level 20, her STEP stat translates to a 1.40x step multiplier.

Kou is useful for farming fragments due to her high fragment multiplier. Once awakened, her skill can boost fragments further on tracks which the player can consistently score high on. Her fragment farming capabilities on harder tracks are only rivalled by an awakened Pandora Nemesis (MTA-XXX). Kou is one of the most reliable partners for fragment farming, and is arguably the best option for players who could not obtain nor awaken Pandora, or are unable to HARD Clear a track.

Kou's awakened form was added on October 8th (Version 2.4.0). This makes her the first side story partner to receive an awakened form.

Skill Details

  • The bonus is applied on the sum of PLAY, CLEAR, PERFORMANCE and FIRST CLEAR fragment amounts.
  • For scores of 9,000,000 and below, the bonus is 10%.
  • For scores of 10,000,000 and above, the bonus is 20%.
  • For scores from 9,000,000 to 10,000,000, the bonus increases linearly from 10% to 20%.
  • The bonus amount of fragments is rounded down to the nearest integer.
$ \text{Bonus Multiplier}=\begin{cases}0.1&\text{Score}<9,000,000\\\Bigl(1+\dfrac{\text{Score}-9,000,000}{1,000,000}\Bigr)\times0.1&9,000,000\le\text{Score}<10,000,000\\0.2&\text{Score}\ge10,000,000\end{cases} $


  • The maximum amount of Fragments theoretically obtainable with Kou at Level 30 is 108, by clearing a Level 11 Beyond chart for the first time and obtaining a Pure Memory. She therefore beats Pandora Nemesis (MTA-XXX) in this regard, only bested by Ayu.


  • Promotional reveal image.
  • Congratulatory image by シエラ (cierra) for lowiro's participation in Comiket 92
  • Kou's full body art as shown in game.
  • Kou's partner icon.
  • Promotional image for Kou's awakened formGo to Twitter status announcing the awakening


Starting Partners HikariTairitsu
Story Partners Tairitsu (Axium)Tairitsu (Grievous Lady)Hikari (Zero)Hikari (Fracture)Tairitsu (Tempest)
Side Story Partners KouLetheEtoLunaSayaKanae
Collaboration Partners SapphireHikari & FisicaTairitsu & TrinHikari & SeineTairitsu (Grievous Lady) & Chuni Penguin
Soundtrack Partners Hikari (Fantasia)Tairitsu (Sonata)
Limited-Time Partners StellaIlithShirabeHikari (Summer)Tairitsu (Summer)AyuEto & LunaYumeNono ShibusawaHaruna MishimaRegulus (MDA-21)Pandora Nemesis (MTA-XXX)Chuni PenguinSiaDORO*C
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