When Zamur reveals he has planned everything from the beginning and Astarte is his creation, he orders Astarte to kill the Castle Master, but she is easily destroyed. Later, Astarte kills Zamur and reveals that she was only manipulating him. Astarte plans to use the former prince as a sacrifice to revive the Lord of Darkness, being successful in one of the endings. The only trap that can kill her is the Banisher. She revives when killed by other traps.
In Kagero: Deception II, if the player gives Millennia the name Astarte, she will start the game with extra Ark. This supports the implications that Millennia became Astarte between Kagero and the first Deception.
While Fiana was the first to be mentioned, Astarte is the first female to make her appearance in the Deception series.