Tarōmaru has the appearance of an average kappa, having light green skin with light yellow patches on his stomach area and around his beak-like mouth, pointy ears and webbed hands. On top of his head is a glossy light blue plates surrounded by short green hair. He has thick, bushy green eyebrows over his eyes, which have black pupils. He has a shell on his back that has a green and light green camouflage pattern, with light brown marginal scutes for its edges. His only clothing consists of a blue vest. While working in Gōhara's company, he wore a long-sleeved light blue suit, a white collared shirt underneath it, a green tie, a pair of square-framed glasses and lacking pants.
Four Generals of Jigoku Arc
Tarōmaru and the kappas of Tono Mountain aid Kitarō and friends in revealing the grave of Chihaya, the lover of Ibukimaru. Together they swim in the lake, creating a vortex that shows the Kidō the grave and allowing him to let his lover rest in peace.
Shirikodama Theft: Just like his fellow kappas, Tarōmaru is able to steal a person's shirikodama, making them lethargic and lazy.