usurper
From LSJ
καὶ νῦν ἀτεχνῶς ἐθέλω παρέχειν ὅ τι βούλει σοι, πλὴν κωλακρέτου γάλα πίνειν → and now I want to provide you with absolutely anything you want, except paymaster's milk to drink
subs.
Tyrant: P. and V. τύραννος, ὁ.
One who claims more than his due: P. πλεονέκτης, ὁ.