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.


Directly referencing her name's origin, Kou is mostly dressed in crimson red.

She wears a crimson red hair band that is shaped like a bunny ear. Her hair is pale pink and straight, going down to her thighs.

She wears a crop-top dress with a separate neck collar with pleated cloth embroidered around it. A crimson red bow tie finishes the neck portion. The torso portion has a white stripe in the middle, with buttons on the sides and the dress splits up further down. Her inner skirt is colored crimson red with a white liner. Ornaments on the edges of the dress finishes the entire clothing.

She wears black heeled shoes as well as black stockings.

She carries with her a teddy bear colored in her hair wearing the same colored tie and hair band as she does.


Kou seems to be one of the more cheerful characters in Arcaea, as she, Hikari, and Hikari (Fracture) are the only partners seen with genuine, blissful smiles, and many of the songs in her dedicated pack, Crimson Solace, are very upbeat.

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
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


Kou is mainly focused on the FRAG stat, and is practically a reverse of Tairitsu (Axium) and Lethe.

  • Her maximum FRAG stat translate to 1.80x fragment multiplier.
  • Her maximum STEP stat translate to 1.40x step multiplier for world mode.

Kou is especially useful for farming fragments due to the high fragment multiplier. For the time (and arguably still is today), she is the main partner to use if you require fragments.


  • 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.

Starting Partners HikariTairitsu
Story Partners Tairitsu (Axium)Tairitsu (Grievous Lady)Hikari (Zero)Hikari (Fracture)
Side Story Partners KouLetheEtoLunaSaya
Collaboration Partners SapphireStellaHikari & FisicaTairitsu & TrinHikari & SeineTairitsu (Grievous Lady) & Chuni Penguin
Limited-Time Partners IlithShirabeHikari (Summer)Tairitsu (Summer)AyuEto & LunaYumeNono ShibusawaHaruna MishimaRegulus (MDA-21)Pandora Nemesis (MTA-XXX)Chuni Penguin
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