Originating from Fujio Akatsuka's *Osomatsu-kun* manga, Totoko Yowai is a recurring character. Her name combines the Japanese word for "weak" (yowai) and a childish term for fish ("toto"), reflecting her common portrayal as a fishmonger's daughter. Her design was repurposed from Akatsuka's earlier character Akko-chan, influenced by his wife Tomoko's name during creation. In the original *Osomatsu-kun* manga and 1966 anime, Totoko lives near the Matsuno sextuplets as a kind-hearted, serious young girl. Patient by nature, she unleashes a violent, sadistic side—including her signature "body blow"—when provoked or frustrated by the brothers' antics. She appears with pigtails, a headband (typically red or pink), and a slender build taller than the sextuplets. Academically capable but notoriously poor at cooking, her personality fluctuates; later manga stories depict her joining the sextuplets in bullying others or scamming individuals, using rougher language. The 1988 anime adaptation significantly shifts her portrayal, emphasizing vanity, greed, and attention-seeking behavior. Obsessed with becoming an idol, she reacts vengefully when ignored and even attempts murder in extreme scenarios like "Sextuplets Squared!". Episodes occasionally revert to her manga-accurate, gentler persona, such as "White Christmas of the Skyline", where she regains confidence as a singer. This version incorporates 1980s trends, including fandom of the band Hikaru Genji and idol-derived slang. As a teenager in the *Osomatsu-san* timeline, Totoko adopts a mature image with straight, long hair and a high school uniform. Publicly, she presents as a humble, academically gifted idol, but privately resents the pressure to be perfect, expressing bitterness through internal screaming. A pivotal event in a "world of memories" transforms her into a monster; she reverts only after accepting she can prioritize being "cute" without excelling in other areas. Throughout the *Osomatsu-san* series as an adult, Totoko retains her classic pigtails and headband but wears modern fashion like a magenta turtleneck and plaid skirt. Her self-centered nature persists, particularly in her pursuit of idol fame. She becomes a "fish idol" to promote her family's shop, enduring a decaying fish-based costume that highlights her comedic struggles. Storylines like "Totoko's Dream" reveal her motivation is purely for adoration and bragging rights, stemming from a spoiled upbringing. Attempts at growth, such as learning self-reliance in "Totoko's Big Panic", are undermined by her quick reversion to laziness and attention-seeking. She remains envious of rivals, correcting herself from calling competitors "ugly commoners" to "powerful opponents" while still fixated on her appearance. Her interactions often involve manipulating the sextuplets' admiration for her benefit. In the film *Osomatsu-san: Hipipo-Zoku to Kagayaku Kajitsu*, her adult self appears briefly during a school reunion scene. She effortlessly receives constant compliments on her beauty, responding with "I know", and immediately detects envy from other women, bluntly addressing them as "uglies". Across all media, her relationship with the Matsuno sextuplets remains consistent: they compete for her affection, but she often reacts with violence or indifference to their antics. While mutual frustration is frequent, she occasionally collaborates with them, and her true feelings toward any individual brother remain ambiguous.