Octoling

Playable Octolings are Octarian fighters that abandoned the Octarian army.

Previously brainwashed by the music of DJ Octavio, these Octolings have heard the Calamari Inkantation, which nullifies the brainwashing effect. Afterwards, they defected to Inkling society in Inkopolis.

Octo Expansion
Octo Expansion introduces the mysterious Octoling character Agent 8, and will allow players to use Octolings in multiplayer upon completing its story mode. The male version of Agent 8 is also the first appearance of a character which is clearly shown to be a male Octoling in-game. Their octopus form is more reminiscent of the squid form of Inklings with a key difference being that their eyes are separated instead of together.

The expansion trailer and teasers also shows Sanitized Octolings using all previous as well as new weapons and specials, including Octarian versions of the Herobrush,  Hero Dualies, and  Hero Brella, as well as each weapon's corresponding Sub and Special Weapon, such as the Dualies Octoling using s and. They've also been seen using the. The physical coloration of the octolings are very different from the normal ones. They are shown to have pale greenish skin, dark teal colored finger tips and blue hair with neon yellow tips.

When the player completes Octo Expansion, they will be able to change from being an Inkling to an Octoling in the player settings. Playable Octolings have different animations for trying on gear, winning or losing, and for taking photos with amiibo. Octolings also have unique hairstyle options as well. As of Version 3.1.0 (Splatoon 2), the Octoling girl has the choice between a hairstyle featuring parted bangs with two long curlier tentacles in front, and one with a small tentacle on both sides of the face and two tentacles tied up into a ponytail. The Octoling boy has the choice between a shaved head with a single tentacle as a mohawk and three smaller ones down a column in the back, and another with a giant afro that resembles a real-life octopus' mantle that changes shape depending on headgear. The Squid Research Lab US Tumblr shows that Octolings are more serious than Inklings and have an interest in technology, e.g. instead of aiming with weapons, they will look more closely at them to see how they work.

While both types of characters are called "Octolings" in English material about the expansion, the Japanese version makes a notable distinction between the player Octoling, called タコundefined, "Octopus" and the enemy Octolings, called タコゾネスundefined, "Octopus-Amazon."

Notable Octolings
Octolings do not have to be playable to be mentioned here.
 * Marina
 * Agent 8
 * Dedf1sh

Trivia

 * When an Octoling is splatted, they will fly off in the form of a small ghost, just like Inklings. They even have their own unique octopus ghost for this.
 * In Marina’s model, she doesn’t seem to have any ears of sort whatsoever despite her wearing headphones most of the time. The reason for this is unknown.
 * In the art book, they were originally going to have Inkling masks and floppy ears like a dumbo octopus. The ideas were discarded except for the curly, above suckers hair and armor.
 * However, the rounded ears may have been reintroduced in Agent 8's design and the design of the playable Octolings.
 * The Octolings' small rounded ears on their models are actually shared the same with Inklings wearing headgear that covers their ears such as the Hockey Helmet.
 * Concept art of Salmon Run show both Inklings and Octolings fighting together against early versions of the Salmonids, suggesting that Octolings were planned to be playable from early on.
 * The playable female Octoling model appears to not be as curvy as the hostile Octoling model.