Isami is Takumi's brother, and the younger nephew of the owner of Trattoria Aldini. Unlike his brother, he has more of a Japanese appearance, with black hair and sharp eyes. Isami is originally shown to be overweight, with his eyes and mouth drawn in a simple fashion, although he briefly became much thinner during the Autumn Election preliminaries. Like Isami, he enrolled in Tōtsuki to hone his skills at the behest of their uncle. Although an equally talented chef, Isami is shown to be less sophisticated than his brother. He was scolded for trying to (and failing to) revise a dish that Takumi had made during their time in the trattoria, and constantly sought to be praised for his cooking like Takumi. Though Isami is supportive of his brother, he does aim to eventually surpass him as a cook. Nonetheless, the brothers are very close.

Spoiler

At the Autumn Election, he presented a tomato-curry calzone that was praised by the judges. He aimed to surpass his brother's score with the dish, but ultimately finished 5th in his block. He tried to support Takumi in his quarter-finals match against Subaru Mimasaka, and was devastated when Takumi lost to his own dish. He and Takumi opened a booth during the Moon Banquet Festival, naming it a branch of Trattoria Aldini, and gained first place in sales in their area. He is targeted as a rebel by the Azami Administration's Promotional Exams, defeated by Eishi on the third exam and expelled.

Isami and Takumi are featured in the Shokugeki no Soma – Fratelli Aldini spinoff manga which focuses on their time in Italy before enrolling at Tōtsuki Academy. (Source: Wikipedia)