I'm a bit rusty with sugi but here's an attempt.
Rigo is a graduate from Uva academy, studies overseen by professor Raifort, who gave him his starting pokémon, a galarian Yamask seeing as he could use a challenge which he passed with flying colors. He has been to Galar, where he evolved his partner Runerigus and caught a few more pokémon for his team, and did his first research on the Galar-Kalos war.
He would later set up base in Lumiose city, for esy access to museums of the highest standard and access to various cities per routes branching off the capital.
His name comes from "marigold" and is also a reference to the lost city of el dorado, rigor mortis (his ace is a ghost), the spanish name Rigoberto (very paldean) and FRIGO RETURNS
I'm not gonna lie, I created him as a self-insert for my yumeship with Jacinthe.