Antonius is a young and promising member of the House Of Malargos, the richest and most prominent family in Ruthgar, the richest and most prominent Satrapy.

He is an idealistic and pious young man, as established when he encounters Prism Gavin Guile enslaved aboard Gunner's ship, and immediately falls to his knees in supplication, crying tears of joy. This is despite the fact that Antonius' family has ample reason to hate Gavin: he maneuvered Tisis Malargos, Antonius' cousin, out of her seat on the Spectrum, and killed Dervani Malargos, Tisis' father and Antonius' uncle, just weeks before during the Battle Of Ru, when Dervani attempted to become Atirat, the pagan god of Green.

Antonius has been shown drafting red, and given that he briefly occupied the position of The Green of the Spectrum, it is likely that he is also a green drafter.