In the inscription on the pedestal Ozymandias calls himself the "king of kings" while also implying that his "works" – works of art like the statue, pyramids, that sort of thing – are the best around (10). Ozymandias thinks pretty highly of himself and of what he's achieved, both politically and artistically. The fact that he commissions this "colossal" statue with "vast legs" points to his sense of pride, while the statue's fragmentary state indicates the emptiness (at least in the long term) of Ozymandias's boast.
Ozymandias's proud statement that he is the "king of kings" aligns him with a number of power-hungry villains, like the Biblical Satan, or even Sauron from Lord of the Rings.