Niko is the playable protagonist of OneShot. They're a child with blue hair with three "whiskers" jutting out from the sides, yellow catlike eyes, and what appears to be tanned skin. They wear a brown overcoat extending over their arms, a long light blue scarf, a brown hat with catlike ears, and grayish purple bottoms that appears to be leggings. They are tasked with returning the Sun to the Tower and saving the World from dying out.
Niko contacts the Player throughout most of the game when in need of help or simply conversation about Niko's and the Player's origins.
Before arriving in the World, Niko lived in a small village with around fifty residents. It is surrounded by a wheat field, which appears in most of Niko's dreams. The tallest building, a clock tower, is only two stories high, and there is a well in the middle of the town.  The village is not on Earth.
Niko first awoke in a bedroom in a house in the Barrens. They encounter the "Entity" by the computer, who tells them that the World isn't worth saving and asking them if they still want to try saving it. Niko soon finds the lightbulb and brings it with them upon exiting the house. They encounter the Prophetbot and inquire to them regarding the World, the lightbulb, the Player and for directions on how to return home. After receiving answers, Niko continues on their quest.
Niko is kind and caring. Being the messiah that the prophecy has foretold, they became determined to reach the Spire and bring the sun back to it in order to save the World, even despite what others say that the sun won't stop the World from dying. Niko is also helpful. A few instances of their helpfulness are seen in the game such as where they repair the rowbot at the dock part in the Barrens and volunteer to find Alula and return her to Calamus. Upon reaching the Refuge, they began to express indecisiveness, as seen where they have trouble choosing whether to bring back the World's sun but risk losing their only chance to return to their home world or whether to shatter the lightbulb, destroying the World instantly and for them to return to their home world. Niko also tends to be curious. They often turn to the Player to ask questions, most of them are regarding any information about the Player.
- It is seen through dream sequences and dialogue that Niko's favorite food is pancakes. Their favorite pancakes are made by their mother, who grinds hazelnuts into the batter.
- Niko has been stated by Eliza to have an ambiguous gender, and Nightmargin an unknown gender.
- Nightmargin stated during a livestream that her headcanon for Niko is that they are actually really tiny and the seemingly huge lightbulb they carry is the size of a regular lightbulb.
- Night also made plenty of joking statements about Niko's canon along with the chat during said livestream, such as them actually having 100 ears, the game taking place in a coma, and Niko having a love for throwing Molotov cocktails.
- Night has also stated that Niko is "Ness", a combination of Niko and Tess during a livestream and in this post, referencing the controversial Game Theorists video Sans's SECRET Identity that claimed that Sans from Undertale was Ness from EarthBound.
- As a running joke, Niko consistently and repeatedly denies being a cat, despite having many features and similarities to one. These similarities include pointy ears on their hat, whiskers extending from their hair, and large yellow eyes. Niko's name is also heavily similar to 猫 neko, cat in Japanese.
- According to Night, Niko comes from Nico, a gender-neutral name.
- Also according to Nightmargin, Nico was changed to Niko as a reference to Nikola Tesla and his work on lightbulbs. On top of the 猫 reference, the name is a triple reference (the third one being to 日光 nikko, meaning sunlight).
- During another livestream, Night referred to what seems like their skin as fur.
- One of the tracks in the OST is titled "On Little Cat Feet."
- During a Solstice run, at one point Niko makes "confused cat noises"
- In the Solstice anniversary stream, Nightmargin confirmed that Niko is not a cat or a person, but rather, a cat-person.
- When playing the game in Japanese, Niko refers to themself in the first-person ミー mii (katakana "me"), forgoing the usually gender-specific first-person pronouns common in Japanese, such as watashi (informal female, formal ambiguous) and boku (informal male).
- The unusual pronoun ミー also doubles as a pun, being a type of onomatopoeia imitating the meow of a cat.
- During the pancakes and chess cutscenes (and probably some others), there was a sprite error with Niko having human ears, like in the original game. It has been vetoed since this update.
- In this post Night made, Niko's age is more or less 8 years old (discounting the original RPG Maker 2003 game, which was released in late June of 2014).
- According to one of Night's posts, Niko was made on December 28, though this may or may not be true in-canon. Thus, in the year of 2021, Niko is "Like, 13."
- Upon interacting with the fox plush more than once, Niko mentions that they have an owl plush back at their home.
- It is brown and yellow and its name is Mr. Banana Bread.
- Niko is afraid of ladders. They mention this more than once whenever Niko examines a ladder in the remake version of OneShot.
- Niko's height is 4 feet (~1.2 meters) according to this post