Astaroth is a Duke of Hell that appears to be an angel riding a snake or dragon. He apparently has extremely foul breath; so foul, in fact, it can be fatal unless one takes due precautions. He can teach the liberal arts with efficacy.
Astaroth was once probably a god of the mid-east; some say he was worshiped by the Philistines while others believe his name is a corruption of Astarte and may ultimately be a demonized derivative of Ishtar. He's also notable for being one of the demons featured in the German myth of Faust. Astaroth's name has also been adopted by many fictional characters in video games and general media.
Shin Megami Tensei II
Astaroth appears in Shin Megami Tensei II as a demon guarding the path to Kether castle, as well as the subject of an optional side-quest.
As Aleph makes his way to Kether Castle he is confronted by what appears to be Lucifer in his human form. He then assumes his true form as Astaroth, a demon of the Tyrant clan, and proceeds to attack the party, claiming that Lucifer has woefully overestimated Aleph's potential. Upon his defeat he asks to be returned to his former self, that of Ishtar, the Babylonian fertility goddess.
If the player fuses an Astaroth and visits the very center of Binah, where a mysterious altar is located, he will ask to be released from his demonic form. Upon consent Astaroth will seperate into Ashtar (counterpart of the Phoenician Astarte) and Ishtar, both of which then become fuseable at the Cathedral of Shadows. Ishtar explains that she was trapped in the Abyss by YHVH in the form of Astaroth, where she wandered for many ages. The gracious Ishtar then grants Aleph a portion of her power, raising each of his skill points by one. She remains at Binah, slowly restoring the fertility of the Abyssal ocean.