The denim-wearing Galsia enemies are amongst the most basic and frequently appearing opposition in the Streets of Rage series. While their standard colour scheme is blue clothing with red hair, there exist many variations with the alternate colours usually signalling greater strength, speed and stamina.
Galsia's typically offer a nominal threat at best, they can do considerable damage when they dogpile a target, and on higher difficulties they move at amazing speeds. They also have a running knife attack which can be problematic for the player.
The Galsias seem to have suffered somewhat in the graphical upgrade from Streets of Rage 1 to 2, as while all of the heroes saw their sprites ramped up in size, the Galsias didn't see a change proportionial to their enemies so that while they seemed the same height as the adult heroes in SoR1, they're as short as the adolescent Skate in the sequels.
In Streets of Rage 3 they gained two new abilities, a leaping elbow drop and far more infuriatingly, the ability to steal health restoring items.
Their names would probably be more properly rendered as "Garcia", but Galsia was the name they bore in the series most popular installment(SOR2), so that's sort of stuck. Their various palette swaps bear different names like Brash & B.T. in Streets of Rage 2, and Carlos and Julio in Streets of Rage 3.
Galsia's graphics seem to be slightly inspired by the goons seen in the first stage of Sunsoft's 1989 game, "Batman," which was released on NES.