|School||Goha 2nd Elementary|
|Anime debut||Yu-Gi-Oh! SEVENS episode 9: "Wonderful Jurassic"|
Kaseki is a tan-skinned bespectacled boy of average height with brown hair that spikes out to the sides in a somewhat similar manner to Jim Crocodile Cook and green eyes. He wears clothing designed for the outdoors; a tan shirt with the sleeves rolled up, thick green pants tucked into brown boots, white gloves for careful handling of fossils, a tan wide-brimmed had with a red band around the base, a brown satchel, and a green bandanna around his neck with a dinosaur face print.
Kaseki is a friendly individual, and despite not being the president of the Dueling and Dinosaur Research Club he is the most forward of the group and seems to make many of their decisions. He is tremendously disappointed after finding that Gossie was not real.
Kaseki's first name is the Japanese word for "fossil", befitting his passion.
After hearing about the appearance of Gossie in Goha City, Kaseki, Hanto and Kan decided to search for it and use it to create their own Jurassic Duel World. After stopping at the Tahayasty Restaurant, they encountered Yuga Ohdo, Tatsuhisa "Luke" Kamijo, Romin Kirishima and Gakuto Sogetsu, who were also looking for Gossie using Yuga's modified Goha Corporation Drone Kaizo. Kaseki introduced the Dueling and Dinosaur Research Club to Yuga and his friends and suggested that they work together to find Gossie, though in reality they planned to use Yuga and his friends to find Gossie and then find it first themselves. After several fruitless stops, Yuga's friends finally determined that Gossie could be at the location of the Relic where Yuga had installed Rush Dueling, though Luke left them before they headed to it. Kaseki, Hanto and Kan reconvened in a bathroom to discuss their plans, unaware that Luke was in the same bathroom, and he confronted them and revealed their plans to Yuga, Gakuto and Romin. Despite the group's treachery, Yuga was still willing to tell them where the Relic was if Kan could defeat him in a Rush Duel. During the Duel, Yuga stated that he didn't believe Kan to be someone who would exploit dinosaurs, and Kaseki agreed, suggesting that they find Gossie after all. But when Hanto suggested they check the construction site where Gossie was rumored to have first appeared, Yuga abruptly tried to stop them from looking, though Luke eagerly joined forces with the Dueling and Dinosaur Research Club. Yuga defeated Kan, but the group decided to check the construction site anyway, only to learn that "Gossie" had been nothing more than heating pipes and a noise produced by one of Yuga's "Roads", much to Kaseki's anger. To make it up to them, Yuga brought the Dueling and Dinosaur Research Club to where the Relic had been, and Hanto sneezed, uncovering seven previously unseen symbols carved in the floor.
- Yu-Gi-Oh! SEVENS episode 9: "Wonderful Jurassic"