You're in the summoning room, you intend to summon a new servant.

When you see that person, you are familiar with her face but only her appearance is different, she is now in the form of a young girl.

"I'm Mom… No, that's wrong, that's my position. My name is Tiamat. I've come as an Alter Ego. Surprised, humanity? If you perish, my defeat will become meaningless. That's why I felt like helping you out" Tiamat said with a soft smile.