Isogashi appears as a grotesque pink yōkai with a malnourished appearance, having visible ribs, three-fingered hands and two-toed feet, both pairs ending in white claws. His head is bald with the exception of the pale yellow hair that reaches his shoulders and goes around his pointy ears, his face is jumbled, having a nose placed on his right cheek, pale purple thick lips with a large tongue sticking out and a yellow eye in the middle of it. His only article of clothing is the orange cloth strapped around his waist, tied by a piece of rope.
His appearance in the sixth anime is relatively the same as before, however his skin is light blue, his hair is green and his frame is less malnourished, but still to visibly thin. His face is more symmetrical now, having his nose right under his large eye, now having a red sclera, and still having pale purple thick lips, but now with a blue tongue. He also wears a dark blue yukata, but leaves it open, with the top covering his forearms.
Episode Nine: Isogashi appears in the ninth episode of the sixth anime adaptation, The Kappas' Work Reform. When Nezumi-Otoko assumes that a workaholic company president is being haunted by Isogashi, he, Kitarō and Medama-Oyaji visit him to see if he is the culprit. However he reveals to them that he has not haunted a human in a decade, he goes on how the world has changed, where humans are overworking on their own everywhere and wonders if the world does not need a yōkai like him anymore. Later when the city is overrun by the Kappas and Kitarō has been subdued, Isogashi finds him and Medama-Oyaji, noting that everyone has become lethargic and lazy because of the kappas. He wonders if it is his time to shine again, entering Kitarō's body, invigorating him to defeat the kappas. After Tarōmaru decides to stop, Isogashi leaves Kitarō's body, complaining that it is over already, just as he was having fun again and goes home.
Invigoration Inducement: Isogashi is able to induce his target with excess vigor and energy to work. He is capable of using it as whip-like energy to increase his target's energy up until exhaustion. Within the sixth anime, he enters the target's body to induce their vigor.