Asmodeus absorb ice and resist physical attacks. Like all flan, they lunge at their opponents and there is a Breaksight (Killsight on low HP) chance when dodging a lunging Asmodeus, and then hitting them right after.
Asmodeus' are more difficult than typical Ice Flans, and at lower levels magic will do little damage to them, and cost a lot of MP. Using cadets which deal heavy physical damage, such as Cinque and Jack, may be preferable at lower levels, but using fire magic damage is always the better option. Additionally, ranged cadets like King and Cater can run up to Asmodeus, and once it lunges, dodge and hit a Breaksight.
Asmodeus is a king of demons known from the deutero-canonical Book of Tobit, in which he is the primary antagonist. The demon is also mentioned in some Talmudic legends. He was supposed by some Renaissance Christians to be the King of the Nine Hells. Asmodeus is referred to as one of the seven princes of Hell, and in Binsfeld's classification of demons, each prince represents one of the seven deadly sins. Asmodeus is the demon of lust.