Octoling

Octolings are the Octarian equivalent of Inklings, and thus are humanoid cephalopods, that became available as playable characters in after beating the  DLC. In, Octolings do not need to be unlocked and are playable at launch, just like Inklings.

Background
Octarians, which include Octolings, are an evolved species of octopus that came to be after rising sea levels destroyed humanity. The long abandoned human settlement of Alterna is the birthplace of the species, after psycho-reactive liquid crystals infused with lingering human thoughts and feelings leaked into the ocean surrounding the settlement, unintentionally accelerated the evolution of octopuses and other species of marine life.

At least 2,000 years before the events of, Turf Wars were established. The original Turf Wars were overseen by Judd, a cat that was cryogenically frozen by his human owner before the Earth was flooded. 100 years before the events of Splatoon, the Inklings and the Octarians of Inkadia engaged in a Great Turf War after otherwise having good relations, when rising sea levels caused disputes over the remaining territory. The young Cap'n Cuttlefish and his Inkling comrades were victorious, forcing the Octarians to retreat to desolate areas such as Octo Valley, Octo Canyon, and take up residence underground.

All playable Octolings from Inkadia began their lives in Octarian domes, eventually becoming soldiers in the Octarian military lead by DJ Octavio. Propaganda kept Octolings fiercely loyal to the Octarian lifestyle, however, during the final boss "Enter the Octobot King!" in, the idol duo Squid Sisters performed the Calamari Inkantation to support Agent 3 during the fight. This performance inspired new feelings within Octoling soldiers that attended, and many began to long for the surface, eventually escaping and assimilating into Inkling culture, hoping to start anew. However, some Octolings, such as Mashup and Shiver, have families stated or implied to have lived on the surface prior to the mass assimilation of Octoling soldiers.

Appearance
Like Inklings, Octolings can switch between a humanoid form and an octopus form.

Their octopus form is different to the ones of enemy Octolings, with two long tentacles in the middle that helps them move, two smaller ones in front resembling a mustache, and four smaller ones on the underside, along with a pair of eyes that are separated and resemble an Inkling squid's eyes. The suction cups are located on the underside of their tentacles, as opposed to their humanoid form having suckers on the top side; their tips, as well as the top of their heads, have a ring pattern on them. Between and, Octolings undergo design changes reflecting their squid counterparts, generally becoming taller, and having more rounded and less squat faces. Additionally, in, Octolings' tentacles have a darker color towards their tips. When splatted, they will fly off in the form of a small ghost, just like Inklings; while its eyes appear white in, they are yellow in , resembling the ghosts of enemy Octolings. The general UI also shows the difference between player Octolings and Inklings, such as the weapon and status indicators, the mini-map, splat messages, and splatted enemy markers replacing the squid icon symbolizing the player with an octopus.

The humanoid form has black markings around their eyes, with both styles having two sharp edges and a thicker underline, where the feminine Octoling has an added dash to their markings. Octolings do not have their markings connect over the middle, having it separated compared to Inklings. Their teeth are also different, having one sharp end tooth on their left side on the top, and another sharp tooth on the right side on the bottom. Their ears are round and asymmetrical, with the right side being flat and the left side being indented, each respectively resembling the fin and siphon on an octopus. Similar to enemy Octolings, the ends of their fingers are pointed, but the playable Octolings do not have these ends being tinted in their ink color. Their eyebrows are also different from Inklings, with males having a half oval shape and females having a curved droplet shape in Splatoon 2. In Splatoon 3, they have more options to choose from. These options are generally rounder than the Inklings' options.

Just like Inklings, Octolings are able to choose from a variety of skin tones, hairstyles, and eye colors. The options of eye color and skin tone are identical to those of the Inklings.

In Splatoon 2, both the male and female Octolings possess two different choices in hairstyle. The female Octolings' first hairstyle, called "Tentacurl", has two thin tentacles in front reaching past the shoulders and two thicker, shorter tentacles in the back, all with curled tips. Their second hairstyle, called "Pony", has two tentacles tied back into a ponytail, with the other two as sideburns. The male Octolings' first hairstyle, called "Punk", features a mostly shaved style, with one large, curled tentacle and three smaller tentacles lined up along their head to create a mohawk, possibly referencing the Octotrooper tentacle. Their second hairstyle, called "Afro", is a round mass reminiscent of a simplified octopus' mantle. This hairstyle notably molds while wearing headgear.

Splatoon 3 has four new hairstyles, to go along with the previous ones, with them all being available to both styles. The first one, called "Tentatwists", has the front tentacles being twisted in spirals. The second hairstyle, called "Octolocks", is similar to the Tentacurl hairstyle, but with the tentacles growing from the middle of the head instead of the right side, and the back tentacles being conjoined together by a mantle structure. The third hairstyle, called "Fade", is shaven all around, akin to the Punk hairstyle, but with four tentacles curling together towards the center of the head. The final hairstyle, called "Surfcurl", is also similar to Punk, but replaces the mohawk with a much thicker tentacle that has been curled into a spiral, strongly resembling a pompadour.

Some Octolings, such as Marina and Shiver have special features, such as plum colored tentacles for Marina, and triangle shaped eyebrows for Shiver, as well as infinity-symbol shaped pupils and peculiar eye markings for both of them. Like enemy ones, Octolings can also have a gradient on their fingers, including Marina and Shiver. As seen on Marina in the Dexterity vs. Endurance Splatfest promo art, the gradient can be present on toes as well. This feature is also present in the playable Octolings for the first time in Side Order. Some Octolings have different colors on both hands, as seen on Mashup from Diss-Pair.

Splatoon 2: Octo Expansion
The DLC story mode introduces the mysterious Octoling character Agent 8, and allows players to use Octolings in multiplayer upon completion. 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.

When the player completes the 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. The Squid Research Lab Tumblr showed that Octolings are more serious than Inklings and have an interest in technology. For example, instead of aiming with weapons, they will look more closely at them to see how they work, they wave around their phones and look at them more closely, and their icons in battles are not seen smiling. Due to have been defecting from the Octarian army, their animations around the Square make them look curious and almost confused.

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 "Octopus" (タコ Tako), and the enemy Octolings, called "Octopus-Amazon" (タコゾネス Takozonesu). The latter specifically refers to the older elite female unit that only a select few of the former can become.

Trivia

 * In Splatoon 2, playable Octolings are represented by pink ink in the Player Settings menu, while Inklings use green ink. Before being added or unlocked, Inkling boys were green and Inkling girls were pink.
 * After Octolings are unlocked, the Player Settings screen has octopuses swimming up with the squids in the background.
 * Unlike Inklings, the Octolings' genders have different animations in the Player Settings.
 * In, Octolings' smartphones have a round shape akin to octopus heads, in contrast to Inklings' arrow-shaped ones. Additionally, they show confusion when trying to use phones.
 * In, Octolings seem to take losing badly in comparison to Inklings, as shown in their losing animations, with many of them falling on the ground in disappointment, boys shaking their fist, and girls crossing their arms. Additionally, when they win, they tend to strike poses, in comparison to the Inklings jumping for joy.
 * Octolings are prohibited from entering Octo Canyon. Instead, the game automatically switches back to the previous Inkling used, customization options included, since that character would canonically be Agent 4. Similarly, the opposite happens when entering the Deepsea Metro as an Inkling.
 * The only instance of Octolings being playable in without purchasing the Octo Expansion was the Squid vs. Octopus Splatfest, where players on Team Octopus had their avatar switch to Octolings in battle. In Inkopolis Square, the avatar remained unchanged. The reverse was true for Team Squid.
 * As seen in The Art of Splatoon, they were originally going to have Inkling masks and floppy ears like a dumbo octopus.
 * A Splatoon 2 Anniversary Famitsu interview with the developers revealed more information about Octolings:
 * Octolings were considered to be playable during the start of Splatoon 2's development, but they wanted an explanation as to why they are playable and to have the player empathize with them along with the new band, Off the Hook, which led to the Octo Expansion being made.
 * In an interview prior to this, the developers revealed that they did consider playable Octolings in the first Splatoon, even before hackers modded enemy Octolings to be playable.
 * Splatoon 2's art director, Seita Inoue, wanted the afro to be the default hairstyle for male Octolings. There even appeared to be concept art for the female one having an afro.
 * Concept art of Salmon Run in The Art of Splatoon 2 show both Inklings and Octolings fighting together against early versions of the Salmonids, reconfirming that Octolings were planned to be playable from early on.
 * Early models of the playable Octolings have been found as early as the Splatoon 2 Global Testfire, where the male Octolings have a hairstyle close to the final "Punk" one, while the female model uses the enemy Octoling hair. The models were deleted in the release version of the game, but entries for the player model type still exist in Version.
 * Some pieces of official artwork feature the playable Octolings having their fingertips colored in their ink color, though this feature is lacking in their in-game model until Side Order.
 * Like Inklings, Octolings' tongues are rarely seen on in-game models and artwork, though Shiver in does often have a visible tongue in her facial expressions.
 * In the announcement trailer of Splatoon 3, while the Inklings and Octolings are being shown individually, the Octoling with the Hydra Splatling had the symmetrical teeth of Inklings, unlike the asymmetrical teeth Octolings usually have. This was later corrected in some promotional art on Splatoon 3 official Japanese website.