While not idols, Ouko and Naomi were shrine maidens in the period before the Great Turf war. They were in charge of Splatfests back when idols weren't a thing. In the current Splatoon timeline, Naomi is still active and stays in Inkopolis Outskirts, while Ouko's status remains a mystery.
Naomi is a beautiful but cold-hearted Broadclub Cuttleling while Ouko is a clumsy yet bubbly Velvet Octoling. They were inseparable until the great turf war suddenly torn their bond apart, and Ouko disappeared without a trace. Now Nomi is an old and respected priestess, still residing in Inkopolis Outskirts.
As a young girl, Naomi caught the eyes of many young Inkling men, but was never interested in them and decided to devote herself to the cat deity. At the shrine she meets Ouko, an older Octoling girl who she would be best friends with for years, until the war broke out. Ouko left and joined the Octarian army for the sake of her family, and Naomi spied on the Octarians with her charm and sent their top-secret information about the next attack and great weapons to the Squidbeak Splatoon.
Even though they're supposed to be against each other's morals, they still try to contact each other through secret meetings and hand-written letters. Ouko hoped that the war soon will be over and tried persuading Octavio numerous times, while Naomi set a couple of captured Octarians free, risking her alliance and loyalty to the Inklings. The last time the two met under Mount Nantai was before Octavio's defeat.
After the Inklings won the war, the majority of Octarians were forced to evacuate into the underground domes, while Ouko mysteriously vanished and left an emotional wound on Naomi, which made her regret supporting the (old) Squidbeak Splatoon in the first place. Now an old and experienced priestess, she left the past behind and moved on with her life as a grumpy old priestess. Even though she's still friends with Craig Cuttlefish, she doesn't want to ever be involved with both Octarians and the Squidbeak Splatoon ever again.
Naomi/ Kobushime Suru コブシメする
She is extremely old and dried out, just like Captain Cuttlefish. Naomi wears a dark red simple kimono, geta sandals, and wields a traditionally made red paper fan. Her hair is tied up into a proper updo with a red sakura-shaped hairpin. Her hair color is dark burgundy fading to a lighter and brighter cherry red with white stripes. Her eyes are covered with round gold-coated shades that support her senior vision. Her skin tone is slightly tanned.
A century before the events of Splatoon, she appears much taller and less grouchy (but more coldhearted?). Her hair is tied into a loose low ponytail tied with a red kelp ribbon, and she wears a white-red hakama (shrine maiden kimono) and wields the same paper fan but with a velvet ribbon attached to it. She has (visible) golden eyes with upside-down triangle-shaped iris and downturned eyelashes with hints of gold. She also wears a red-white cuttlefish-shaped mask that covers the right half of her face.
When judging turf war results, she will wield a gohei that matches the team color. She represents the player's team.
Ouko/ Itame Takou 炒め 多幸
Her skin tone is tanned. Ouko's hair is light greenish-grey fading to olive green. Her slanted eyes are dark velvet with neon green four-point star-shaped irises (like Octavio's X-shaped scar). Her hairstyle is low short pigtails tied with a neon green kelp ribbon. She wears the same outfit as her fellow shrine maiden, but the red is replaced with dark green. She wields a green bamboo broomstick that can be used for casual turf war and cleaning the shrine's backyard. She also wears a green-white octopus-shaped mask that covers the left half of her face. Her fingers fade to a lime green gradient.
When judging turf war results, she will wield a gohei that matches rival team color. She represents the rival team.
- They're designed after the early shrine maiden concept art of Splatoon. Originally, the Squid Sisters were going to be shrine maidens, but it felt too traditional for the game and the idol concept was used instead.
- Their "English" names are a pun based on Okonomiyaki, a Japanese pan-grilled savory pancake that contains squids/octopus as one of its fillings. ("Oko" is changed to "Ouko", and "Nomi" is changed to "Naomi".)
- Naomi's Japanese name, Kobushime Suru, is based on "kobushime" (Japanese for broadclub cuttlefish) and "surume" (Japanese for dried squid). Half of her name is based on food because both Captain Cuttlefish and Octavio's Japanese names also are (look up on Google for Atarime and Takowasa). Ouko's Japanese name is based on Tako-itame, or Nakji-bokkeum, which is a Korean stir-fried octopus dish.