Riguel was believed to be loyal to the Band of the Hawk as he always put his life on the line when in battle.
Golden Age Arc
Riguel was part of a small group led by Corkus to attack Guts right after they first witnessed him in his battle with Bazuso. Due to his success, it was assumed that Guts was carrying a large sum of money, which Corkus' band intended to steal. The plan fails immediately, as predicted by Casca, though Griffith approved of it.
Corkus commands Dante and Errol to take care of Guts. When both of them are easily defeated, Corkus commands Riguel to take care of him. Having witnessed Guts' strength, Riguel declines Corkus' command.