From Bulbapedia, the community-driven Pokémon encyclopedia.
Hiromoto SIN-Ichi (Japanese: ヒロモト森一 Hiromoto Shin'ichi) is a manga artist, born on January 4, 1966.
He was the character designer and art director for Pokémon Colosseum and Pokémon XD: Gale of Darkness. He also was the author of the STONe and Star Wars: Return of the Jedi manga series.
His name is written as "Hiromoto SIN-Ichi" in the Super Smash Bros. Melee credits, as "Sin-Ichi Hiromoto" in the English versions of the STONe manga series, and as "Shin-ichi Hiromoto" in the English versions of the Star Wars: Return of the Jedi manga series.
Manga Force, Hiromoto SIN-Ichi's official website (Japanese)