TV-Series
Description
Fisher Sky is a character from the Alien Residential Area of Mutsuba Town, and their true nature is that of a colony of skyfish, a type of cryptid that appears as elongated lime green visual artifacts. Rather than a single entity, Fisher Sky is a collective of numerous small flying creatures, each individually conscious. Because they are composed of many separate beings, they refer to themselves using plural pronouns, such as "we-tachi," and have a habit of ending their sentences with the verbal tic "sky".

In their natural, dispersed form, Fisher Sky possesses tremendous speed and agility, which allows them to remain unseen by most people. They can also interfere with electronic devices, such as traffic lights, to hamper pursuers. However, their primary ability is to merge their myriad fragments into different forms. The most frequent and recognizable of these is an assumed persona known as "The Informant," which appears as a young boy with messy green hair, wearing a brown detective-style trench coat over a tuxedo, and a fedora. Beyond this humanoid guise, they have demonstrated the ability to mimic other specific individuals, such as Yuhi Ohdo, and even inanimate objects, such as a functional Duel Disk deck container. They can also use their numbers to form simple shapes, like the letters in a sign. Each individual skyfish fragment is assigned a specific body part to construct when forming the Informant, with each fragment given a code name like "Navel Number 81".

Personality-wise, Fisher Sky embodies the traits of a classic informant. They are mysterious, privy to secret information, and show a great fascination toward things they do not yet know. They are proud of the idea that the one who obtains information obtains the universe and values their position of informational power. Their aversion to reflective surfaces, such as mirrors and windows, is a notable quirk, as their abilities are hindered when their true form cannot hide, forcing them to coalesce into a tangible shape. After initially taking an interest in the alien Velgearian Yudias Velgear following his duel with Zuwijo zir Velgear, Fisher Sky began researching him and the organization UTS.

Their role in the story begins when the Ohdo twins, Yuhi and Yuamu, seek them out for information regarding Yuna Goha. Fisher Sky actively avoids the main characters, using their unseen speed to haunt and warn them. They are eventually trapped in a room filled with reflective surfaces by Yuamu, which forces them to take their humanoid form and reveal their identity. This leads to a Rush Duel against Yuamu, where they showcase their information-gathering skills. Having researched Yuamu's deck, Fisher Sky builds a strategy specifically designed to counter her LIGHT Attribute "High Tech Dragon" monsters. They are ultimately defeated because Yuamu had, at the last moment, secretly added new and unknown cards to her deck, introducing an unpredictable element that their intelligence could not account for.

Following their defeat, Fisher Sky provides the twins and Yudias with key information, suggesting that Yuna Goha is likely at Badloon Castle, the stronghold of the Rovian Bandits, and that they must raise their "Macho Rank" by dueling at the Coruffium arena to enter. They are subsequently captured by Yuna Goha herself, who sucks them into a vacuum cleaner and traps them in a plastic bag. In captivity, they are subjected to abuse from Yuna, but the rough treatment creates a small hole in the bag. Fisher Sky sends their smallest fragment, Navel Number 81, to escape and find Yuamu for help. This fragment plays a key role in infiltrating Badloon Castle, using the vents to guide Yuhi and Yuamu inside. Fisher Sky and their fragments continue to act as a source of information, working to uncover secrets, such as investigating the Ryugu brothers for the Rovian Bandits, though these efforts are frequently met with danger and capture.

In terms of dueling, Fisher Sky uses a "Sky Fossil" deck, which consists of WIND Attribute Zombie Type monsters that are based on ancient Cambrian life forms like Anomalocaris. Their playstyle reflects their information-based philosophy, relying on anti-LIGHT Attribute strategies, manipulating attack points, and managing resources in the Graveyard to control the flow of the duel.