Lemonpai operates as a heavily armed cyborg soldier under the civilian identity of Tsukasa Ichimonji. When transformed, her appearance and capabilities shift into a Mega Man-like form with significant mechanical augmentations. Her primary arsenal draws from military barracks stock, featuring heavy equipment like rocket launchers. Concealed weapons within her armored suit include arm-mounted launchers firing small missiles and an electrically charged striking technique called the Thunder Punch.

Driven by a quest for the legendary mahjong tiles known as the Legendary Pai, she aims to collect them all for a single wish: to become fully human and transcend her cyborg existence. This goal intertwines with her fundamental need for love and acceptance.

She collaborates contentiously with four other female characters—a transforming superheroine, a bunny alien, a dominatrix maid, and a magical girl—to defeat monsters manifested from mahjong tiles. Despite their shared objective, competition and frequent bickering arise among them, particularly when claiming tiles after monster defeats. Her interactions emphasize her military discipline and the tension between her mechanical nature and human yearnings.

This character originates from the "Idol Janshi Suchie-Pai II" video game, with her OVA depiction maintaining consistency in core concept and visual design.