Estrid Mirjasdottír (エストリッド・ミルヤスドッティル), mostly called by her nickname Est (エスト), is the younger sister of Effie and Edda and the daughter of Mirja.

Est doesn't appear in the TV series or the OVA.


Despite being 11 years old, Est is already a curvaceous girl with a very prominent chest. She has small horns above her head, pointy ears and a cow-like tail like any other Kýlbringa. Her long hair is tidied up in a ponytail and adorned with a dark ribbon. Est wears a miniskirt, but no shirt. Instead, suspenders cover her nipples. She also wears a bell as a necklace.


Edda is a very energetic girl with and innocent personality. Like any other Kýlbringa, she has a motherly disposition towards those younger or smaller than herself. She adores her sister Effie. Up until Naoya's arrival she didn't seem to be aware of men.


During the stay of Rotte and her group at Mirja's house, Est comes running inside to meet her sister Effie. Her mother asks her to be more polite since her highness Rotte and her companions are guests. She apologizes and introduces herself properly. Both Naoya and Rotte are shocked to hear that she is only eleven years-old, yet she already has an ample bosom and the proportions of an older girl. Asuha compliments her for having big boobs despite being the same age as her. When Ini introduces herself, Est's Kýlbringa nature awakens to the cuteness of Ini and takes her outside to play with her and other villagers.

After some time, Ini and Est return. When inquired, Ini tells them that she become the toy of the young girls at the village square. Est apologizes for the crowd, but Ini is grateful, telling her that it was worthy for the milk, having been able to drink the milk of Est (which was strawberry flavored) and the other girls.

When Mirja tells Rotte and her group that the bath is ready, she tells Naoya that he can use the bath after the girls are done. Est then notices that Naoya, who had entered the village disguised as a maid, is now wearing a different outfit and has a wig in his hands. As Naoya is about to answer that he was crossdressing, Effie interrupts him and tells Est that the wig is a fashion item and that the other clothes were dirty.

Some time later, Naoya is walking outside for a while in his maid disguise when he suddenly has the need to pee due to drinking a lot of milk while chatting with Effie and Mirja. Since he is away from the manor and doesn't really want to use a women's washroom, he decides to relieve himself there, reasoning that he is alone. Not far from there, Est is running around trying to locate Naoya to tell him that the bath is free. She is wondering why Naoya couldn't bath together with them. Est finds Naoya at the exact moment that the latter is peeing. Curiously watching and without revealing herself, at first Est seems confused until she suddenly understands that Naoya is a man and thinks that this is big. That night, when Mirja is saying good night to Rotte and her group, a blushed Est can be seen watching at Naoya's loins from afar. Moments later, Rotte's group hears noises from outside. It is then revealed that Est had told other girls that Naoya is a man and they are now lining up and waiting to receive Naoya's seed. Ini then comments that that's the reason why men aren't allowed inside the village since this would happen.