Nenga leads the Nenga school of ninja, a large bear endowed with significant powers and wisdom. He exhibits distinct quirks: assigning simple, easily remembered names to objects and frequently distributing Pocky snacks.

As head instructor, he trains students including Manmaru, a young penguin lacking conventional physical prowess brought to become a ninja; Tanutaro, a short-tempered tanuki prone to frustration and arguments; and Tsunejiro, a kitsune (fox) who enjoys mending clothes but harbors a significant fear of dark, enclosed spaces. Nenga's leadership involves navigating rivalries with other ninja factions like the Koga (monkeys) and Iga (dogs), and addressing challenges from the Dobe, a group of Nenga school dropouts.

Personality assessments classify Nenga as an ISTJ, reflecting traits like detail orientation, systematic thinking, logical decision-making, and practicality. He strictly adheres to the Ninja code, emphasizing discipline, order, and respect for traditions. His introverted nature manifests as a preference for solitary work or interactions only with close acquaintances like fellow ninjas, avoiding small talk while speaking decisively when necessary to correct errors or defend principles.

He is also identified as an Enneagram Type 6w7 ("The Loyalist"), displaying strong loyalty and dedication to his students, particularly Manmaru. This highlights his cautious, security-oriented mindset, occasionally bordering on paranoia regarding potential dangers. He seeks guidance and reassurance from authority figures, aligning with his sense of duty and protective instincts. The "wing 7" aspect introduces a secondary influence of enthusiasm and lightheartedness, occasionally tempering his inherent wariness.