We have to admit, we were a wee-bit tempted to put Talus with the villains because, well, Talus does some pretty questionable stuff in this poem. By far the most controversial "good-guy" character in The Faerie Queene, Talus' machinating, cold, and ruthless dispensation of "justice" really makes you question the justice he claims to be dealing.
Talus functions as Artegall's sidekick, and since Artegall is the manifestation of justice, we can see Talus as its enactment. In other words, Artegall makes judgments and Talus carries them out. He's the muscle.
This arrangement allows Artegall to be somewhat removed from the actual enactment of "just" punishments, which suggests that there is perhaps a tension between justice as an ideal and justice as a reality. Does justice somehow cease to be just when it actually has to act? We'll leave you to ponder these deep questions.
Oh yeah: Talus is also an iron, mechanical robot-man, which is just awesome.