Kururu holds the rank of Sergeant Major and serves as the Strategy and Communications Staff Officer for the Keroro Platoon. His distinctive yellow skin resulted from a childhood incident where he fell into a vat of curry, permanently dyeing his originally blue complexion. He wears orange headgear featuring a small yellow spiral symbol and displays a prominent red spiral on his abdomen. White glasses with spiral patterns typically conceal his eyes, though rare moments reveal them as dark or olive-green when removed or during transformations. Multipurpose headphones are his signature accessory.

He combines intellectual genius with social detachment. Kururu struggles with empathy, avoids eye contact, and often isolates himself, displaying inappropriate social reactions. He maintains extensive archives of seemingly trivial recordings and enjoys unpleasant sensory inputs like nails on a chalkboard. This behavior, coupled with elaborate pranks that occasionally cross into cruelty, earned him the nickname "Yellow Devil." However, this demeanor is partly a calculated facade; internal dialogues and labeled thought processes reveal meticulous control over his image to appear heartless. He expresses frustration when perceived as unpopular or unlikable, indicating self-consciousness about his reputation.

Kururu's technical expertise makes him indispensable. He designs inventions ranging from surveillance devices to combat machinery, including the Ryusei idol android and an age-altering gun that accidentally transformed him into a baby. His laboratory contains extensive technological resources, and he demonstrates skills like DJing. He obsessively consumes curry and exhibits a weakness to extreme spiciness, while also fearing the purity of Angol Mois due to the guilt it induces.

Subtle development occurs throughout the series. While early episodes emphasize his "depressing" demeanor, prolonged interaction with Earth softens him. He acknowledges this change, occasionally assisting teammates without direct compensation during crises and often being the last to abandon Keroro during internal conflicts, displaying loyalty. His relationships deepen: he shares mutual understanding with his human partner Saburo, collaborates with Aki Hinata on robotics, and gradually builds rapport with Fuyuki Hinata. Though frequently antagonistic toward Natsumi Hinata—partly due to invading her privacy—she demonstrates familiarity with his preferences.

In the *KeroZero* special, chronicling the platoon's pre-Earth departure, Kururu participates in the initial mission from Keron Planet. His transformations include becoming a dragon during the fourth movie under Shion's influence, adopting a female idol persona (Kururuko) via Sandstar exposure, and using a "Handsome" invention to alter the platoon's appearances.