TV-Series
Description
Kururu, also known as Kululu, is the Keronian Sergeant Major serving as the Communications Expert and Strategic Operations Staff Officer for the Keroro Platoon. He was originally a light blue color as a younger tadpole, but his skin was permanently dyed its current curry yellow after he fell into a large vat of curry made by Keroro. His appearance is characterized by an orange cap featuring a yellow spiral, a red spiral emblem on his stomach, and a pair of shiny glasses with distinctive black spirals on the lenses. He typically wears a multipurpose set of headphones and has a perpetually stooped posture.

Kururu possesses a highly complex and often unsettling personality. He is widely regarded as the brain of the platoon, yet his demeanor is extremely mischievous, deceitful, and enigmatic, leading many to label him a mad scientist. He exhibits a lack of empathy, social difficulties, and a tendency to avoid others, often showing restricted interests and becoming bored easily. He is known for his distinctive laugh, which sounds like "kukkuk," and he derives strange pleasure from unpleasant sounds, such as nails on a chalkboard. Kururu appears to be self-conscious about his unpleasant nature, becoming upset when referred to as ugly or unlikable. Despite his cold exterior, there are indications that his creepy and heartless behavior is a carefully controlled facade meant to conceal his true thoughts or keep people at a distance. Beneath this veneer, he is shown to be a fairly good person who cares for his friends, though he frequently takes his practical jokes too far.

His motivations stem from a deep-seated boredom and a love for trouble, as he himself has stated that he does not want to be considered an awesome person. He takes pride in his distorted personality and makes no effort to change it, even going so far as to design his personal laboratory, known as Kururuz Lab, in the shape of his own face. In his official role, Kururu is responsible for intelligence, planning, and the creation of nearly all the gadgets and mecha used by the platoon. Although his rank is higher than that of the platoon leader, Keroro, he is not the commander due to his unnerving disposition. He was once demoted from the rank of Major after hacking the Keron Army network simply because he was bored.

Kururu maintains a stable, if unusual, place within the platoon, and it has been shown that the group cannot function effectively without his inventions and intellect. He generally fulfills Keroro's outlandish invasion requests without complaint, and while Keroro is reluctant to introduce him to others, he consistently relies on Kururu to build his schemes. He shares a unique bond with his human partner, Mutsumi Saburo, as both are misunderstood geniuses who get along remarkably well despite Kururu's faults. In contrast, he has a contentious relationship with the brawn-over-brains Giroro, often using the corporal as a guinea pig for his latest, often dangerous, inventions. This dynamic later evolves into a running gag where Kururu appears to develop a strange crush on Giroro, much to the latter's horror. He also exhibits perverse tendencies, such as secretly monitoring the Hinata family, particularly Aki and Natsumi, for his own amusement. Despite his misanthropic nature, he is shown to have a fear of pure-hearted individuals like Angol Mois, whose innocent stare is enough to intimidate him.

Kururu's development is subtle, but his hidden depth is occasionally revealed. When the Soul Diver is used to explore his mind, it is shown that even his thoughts are carefully organized and labeled, proving his actions are highly controlled. In serious situations, he drops his mocking demeanor to offer sound, logical advice to the platoon, revealing a sharp wisdom beneath his cruel pranks. One of his most notable abilities is his genius-level intellect, which allows him to construct advanced technology. His headphones are a primary tool, capable of connecting to all machines, erasing memories, or emitting special ultrasonic waves. He is also nearly indestructible when it comes to his love for curry, able to withstand even the spiciest varieties and often seen bathing in it.