Retasu has light skin, blue eyes, and green hair, which she wears in two long braids. She also wears a pair of thin-framed glasses. Her school uniform consists of a white sailor-style blouse with a red ribbon, a black pleated skirt, knee-high socks, and brown shoes.

As a waitress at Café Mew Mew, Retasu’s uniform follows the same design as the others but is distinguished by its dark green color scheme, reflecting her theme color.

When transformed into Mew Lettuce, her hair shifts to a brighter green, styled into a loose ponytail, and her eyes change from sky blue to bright green. She wears a strapless green dress with a skirt flaring out in a petal-like design, along with green garters on her arms and left leg. A green choker with her Mew Pendant hangs around her neck, decorated with white lace that also trims her garters. Her footwear consists of knee-high green boots, and she sprouts a pair of long white fin-like antennae extending down past her feet. Her Mew Mark, resembling two curved fish, is located on her chest.

In Tokyo Mew Mew New, Retasu’s outfit receives several updates. Her leotard is replaced with a tight green skirt, and her pendant is reimagined as a green ribbon with a heart-shaped gem at the center. She also wears a larger, lighter ribbon behind her choker, and her garter now features an attached ribbon. Her fingerless gloves include a white band with a small green heart gem, while her boots are redesigned as lace-up style. Her ponytail is split into two curled sections resembling ocean waves, and her white antennae are repositioned at the back of her flower-petal skirt for a sleeker design.

Retasu is portrayed as a gentle, polite, and timid girl who often struggles with self-confidence. She speaks in a consistently formal manner, even with close friends and family, reflecting both her shyness and her reserved nature. Initially hesitant to assert herself, Retasu gradually becomes more confident after forming close bonds with Ichigo Momomiya and Minto Aizawa, whose friendship helps her open up and grow emotionally.

Though she prefers to avoid conflict, Retasu demonstrates courage when the safety of her friends is at stake. She will willingly put herself in danger if it means protecting others, showing her quiet strength and loyalty beneath her timid exterior.

As a Civilian
Retasu is depicted as creative and artistic, with a particular talent for tailoring, often making dolls in her spare time. She is intelligent and demonstrates some ability in hand-to-hand combat, though she rarely relies on it. At the beginning of the series, Retasu is unable to swim, but through her transformation and training as a Mew Mew, she eventually overcomes this weakness.

As a Mew Mew
Retasu, as Mew Lettuce, possesses powers linked to her fusion with the finless porpoise. She is the only Mew Mew capable of breathing underwater. In the manga, her legs can transform into a porpoise tail, greatly enhancing her swimming ability; in the 2002 anime, this trait is only activated in the presence of Mew Aqua. Retasu can also manipulate water telekinetically, an ability that appears to be influenced by her emotional state, her powers grow stronger when fueled by intense feelings.

As a Mew Mew New
In Tokyo Mew Mew New, Retasu retains her ability to breathe underwater and transform her legs into a porpoise tail. In addition to manipulating water, she can generate air bubbles to sustain others underwater, witness past events, and sense the presence of others within bodies of water. These expansions of her abilities emphasize her heightened connection to aquatic environments.

The name Retasu (れたす) is a direct transliteration of the English word “lettuce.” This reflects her assigned theme within the Mew Mew team, as each girl’s name is linked to a food item or natural motif.

Her surname, Midorikawa (碧川), combines the kanji 碧 (midori), meaning “green” or “blue,” with 川 (kawa), meaning “river” or “stream.” Together, the name evokes imagery of nature and water, complementing her fusion with the finless porpoise and her aquatic powers as Mew Lettuce.