Tell us more about this infinitus fella. Also, is that a man-skirt he's wearing?
Infinitus is, in the Sintuplets universe, basically what Satan is in Christianity: the source of all evil, the great manipulator, the origin of ALL SIN (so much so, in fact, he owns copyright patents to it! Not even his group, the Sin Dragons, can sue him for it!) And is the King-Emperor of the Sin Dragons.
He's an ass to anyone who isn't his children, his wife Lunaria, and his head butler Faustius. He will maim and kill anyone who so much as makes him even a little mad, but he's a great tactician, the enemy of The Great One, and a damn fine planner once he gets an idea. On the flipside, Infinitus is gentle with Lunaria, absolutely adores the sintuplets (when he isn't pitting them against each other for his amusement, or controlling them using commands he installed on them when they were barely eggs in Lunaria's womb), and very respectful of Faustius' ideas when the imp is eager to talk about it.
Infinitus is EXTREMELY short-sighted, and beyond seeing things that benefit him in the long run, the guy never picks up on the consequences of his actions. Heck, one of the consequences of his actions is the possibility of the Sin Dragons selling his children - Infinitus' future generals of his army - out into the slave trade for purification of their Sin Dragon traits...
As for the 'man-skirt', that's actually his wings! Here's a picture of Infinitus in his dragon form.