Agrat bat Mahlat (אגרת בת מחלת) is a demon in Jewish mythology.
Mahlat and Agrat are proper names, “bat” meaning “daughter of” (Hebrew). Therefore, Agrat bat Mahlat means “Agrat, daughter of Mahlat.”
In ancient texts
In the Rabbinic literature of Yalḳuṭ Ḥadash, on the eves of Wednesday and Saturday, she is “the dancing roof-demon” who haunts the air with her chariot and her train of 18 messengers/angels of spiritual destruction. She dances while her mother, or possibly grandmother, Lilith howls. She is also “the mistress of the sorceresses” who communicated magic secrets to Amemar, a Jewish sage. In Zoharistic Kabbalah, she is a queen of the demons and an angel of sacred prostitution, who mates with archangel Samael along with Lilith and Naamah, sometimes adding Eisheth as a fourth mate.
According to legend, the spirits that Solomon communicated with and its leader Agrat were all placed inside of a genie lamp-like vessel and set inside of a cave on the cliffs of the Dead Sea. Later, after the spirits were cast into the lamp, Agrat bat Mahlat and her lamp was discovered by King David and after this he became very close to its leader spirit Agrat and so she mated with King David and bore him a cambion son Asmodeus, king of demons. Some scholars claim that Asmodeus was only the king of David’s personal demons like greed, lust, etc., but the other camp of scholars in the argument is that Asmodeus was king to even yet more unnamed demons.
About 1000 years after the era of Solomon and David, another widely known intervention occurred known as “The spiritual intervention of Hanina ben Dosa and Rabbi Abaye” which ended up curbing her malevolent powers over humans.
Some authors, such as Donald Tyson, refer to them as manifestations of Lilith. In additions to being manifestations of the first Lilitu known as Lilith, Agrat and her sisters are indeed Lilith’s children she had while she was in Lilitu form and Agrat is humanoid/demonoid entity that came from Lilith when she was in her Lilitu form known as a Lilin.