Hiro's first teammate is a quiet gunslinger named Alex. They are someone who struggled to land jobs on their own in the guild due to their timid nature. They can get the job done - effectively too. But people just wouldn't give them a chance. It wasn't until Hiro and Alex crossed paths that they were given their first real chance. He could see through their meek personality and saw not only a valuable teammate, but a good friend. They are under the tutelage of Wendell - who shares his knowledge of gunslinging with them.
They use twin Elemental Blasters - which are powered by stones like Hiro's gloves. They shoot various projectiles, depending on what stones are in use, which also changes when the twin blasters are combined into their rifle configuration.

Oh and you can call Alex by any pronoun. They don't mind or have any preference.

Artist is my friend Aurum on Discord