In spite of her appearance which looks like a young girl, Seth is older than any other people in the New Human Empire. As someone has lived for more than 900 years, she has matured—probably more than anyone else—it's just that her undercover eccentricity that hides the more mature sides of her. She acts as the mother figure for all of the Methuselah residing in the Empire.

As a mother, Seth is very loving, protective and caring. She establishes a land for cemetery which she named "The Island of Beloved Children". At first, you might think that her reference of "children" is mere formality, but apparently, it isn't. She really cares about them. When Mirka Fortuna is confirmed "dead", she is the one who led the service.

When a child makes a fault, a mother will give a punishment—only to make him memorize that it was not a good deed, and that he shouldn't ever do it again. She will still love him anyway. Seth's genuine motherly love is very visible after she finds the "traitor" of the Empire. When Suleyman is proven to have committed treason, Seth was ready to punish him, but she still talks to him and gives him the chance to speak. She doesn't even dodge when he attacks him in the palace—and he purposely misses. When the man is dying, she even kneels down and puts him on her lap—she doesn't care about his puddle of blood which can discolour her fancy Empress clothes—and finally, gives him a rather peaceful death.

"Heed me, 'Puppet Master'. I will let you off with a warning today, but... the next time I see you, I won't show any mercy. So, start running for your life. Run to the corners of Earth. No matter where you escape to, I will force you into extinction. I will catch you, and punish you. Ion, Suleyman... even Radu... You [Rozenkreuz Orden] people have done unforgivable things to my children. I will... have my revenge." - Seth to Dietrich, Act 33 Swallowtail

When a child gets hurt because of someone else, a mother will be furious. Seth learns that the real culprit behind all of it was Rozenkreuz Orden. One of the members, Dietrich von Lohengrin toys with Methuselah's dead bodies and disguises himself as Radu Barvon—a noble who was supposed to be dead. He also uses Suleyman for his own benefit, and almost has Ion killed. To Seth, the Orden has done unforgivable things to her beloved children. Enraged, she confronts Dietrich, activates her Krusnik, and makes an oath that she will have a revenge to the Orden.