Gumchi is an extraterrestrial entity that crash-landed on Earth centuries ago inside a meteor fragment from its obliterated home world, finding refuge in Iga village. Shinobi clans constructed a shrine for it and guarded it across generations. Originally named Dangochi, it hails from a planet destroyed by Space Ninjas.

Physically, Gumchi resembles a large glob of yellow gum. It possesses a round head and a spread-out, segmented base. A purple shuriken rests on its torso, and it wears white socks with purple and brown geta sandals. Its face features a dark purple mask-like area framing magenta eyes, two prominent buck teeth, and a gum protrusion resembling a third bottom tooth. A kendo stick is typically attached to its back.

Gumchi displays a playful, eccentric nature, communicating through gibberish. It willingly allows children to stretch or compress it, fostering a perception of harmlessness. However, it harbors significant latent power, capable of transforming into weapons like an ippon katana during critical moments to defend allies, such as saving Kappei and his grandfather from attackers.

Protected by shinobi for centuries due to its perceived potential, Gumchi remains largely enigmatic, attracting the attention of ninja groups and Space Ninjas seeking to exploit it. Introduced to Kappei as his family's ancestral charge during an attack on their residence, Gumchi transformed into a weapon when assailants demanded its surrender, enabling Kappei to defeat them. Impressed by Kappei's resolve, Gumchi bonded with him. Gen'unsai then tasked Kappei with Gumchi's protection during his training in Komerica.

Gumchi subsequently accompanies Kappei on his training and missions. It participates in sessions with Van under Genryusai's supervision and appears in Oedo, where Kappei uses it to demonstrate Space Ninjas' ability to absorb objects and gain their powers. Gumchi shares a similar gum-like composition with Space Ninjas, suggesting a possible common extraterrestrial origin.