Isao

Mateo is a character of the day who appeared in The Crystal Onix (EP089).

Mateo and his younger sister Marissa live on Sunburst Island in the Orange Archipelago. Mateo grew up helping his grandfather at his glass shop. After his grandfather's passing, Mateo decided to follow in his footsteps and now operates the old shop. However, he had recently been suffering from artist's block and became increasingly frustrated by his lifeless and lower-quality glass products. One shop owner yelled at Marissa, claiming her brother was ruining the glass business on the island.

Mateo's ultimate goal was to capture the legendary Crystal Onix. With the help of Tracey's Venonat and Marill, he found the Pokémon in a nearby cave. Using his Pokémon, he weakened it, but out of nowhere, decided not to capture it. He later told Ash and his friends that just the act of seeing the Crystal Onix had inspired him.

When he returned to his glass shop, just like his grandfather, Mateo was able to make much better glass pieces, and soon, his business greatly improved. Mateo then gave Ash a Pikachu glass figurine as thanks.

(Source: Bulbapedia)