Saja (沙蛇) is one of the Six Ancestors of Lamia and Harpy bloodline, with their genes mixed within her body. She boasts an arrogant nature and is very clingy and relentless to males she likes and won't be satisfied until she makes him into her sexual slave. There is an unconfirmed theory that she might be the second monster lord.
(Updated profile from ToroToro's blog May 1, 2020, roughly translated)
The leader of the Six Ancestors, and a great monster who is highly trusted by the Dark God. She bears the characteristics of lamias, harpies, and dragons, and possesses tremendous physical and magical capabilities.
Although there is no clear superiority or inferiority among the Six Ancestors' powers, there is balance and affinity between their specialties. Saja has the greatest overall fighting ability amongst the Six Ancestors, and is known for being the strongest among them. Her power is said to rival Heaven's most powerful angels, Micaela and Lucifina.
In the parallel world known as "Makai" ruled by the Dark God, Saja does not rule over a city. She is the confidant and guardian of the Dark God, and rarely leaves her side. The Dark God does not move from her castle on the Monster Continent, so Saja leads the Dark God's armies as her adjutant. Saja has strict and level-headed personality, but she appears to dislike excessive cruelty. She is deeply loyal to the Dark God, and it is rumored that she could become her successor.
Saja dislikes atrocity, but as she is a monster, she finds no greater pleasure than in playing with men. She rapes defeated men and feeds upon them for her own enjoyment. As a yoma, it isn't unethical for her to squeeze challengers to death. That is, she is only exercising her natural right as the victor.
Saja first appears in Part 2 of Monster Girl Quest: Paradox. While Raphaela is showing Luka the alternate Esta in an attempt to sway him to her side, Saja invades the world using a projection of herself. Addressing Luka as "Worldbreaker", she tells him not to listen to Raphaela, as the world she promotes is one where people have no free will and are merely slaves to Ilias. Raphaela retorts that Ilias' control is necessary, as humans will make the wrong choices if left alone, to which Saja responds that the freedom to make mistakes is necessary for life to have value. They continue arguing in this manner, eventually demanding that Luka listen to them and not the other. Luka has the choice to agree with one of them or remain undecided.