Basically, the Tree of Yggdrasil is the biggest majorest magic power in their world, wowie, so it’s like super important. There are four stars that protect the tree, one of the stars is the evil star of the east. Out of the three seals that were put on Luciana (mc) one of them was the seal of the east star. By the end of chapter 13 big bro reveals that he actually made a contract with the evil star of the east 3 years ago… how is that relevant? IDK LOL probably to explain in the later chapters why Luciana is charmed by the evil star of the east. Now as for the other seals, they were revealed to be the seal of the four stars and the seal of the Wisteria duchy (the three bros and the dead fourth). They are all like OMG WTF!!! because the fourth brother who died years ago was the only one in the family who carried the charm ability. So they are like… how the heck is our seal on you when the only one who could do that is dead!!! I think there’s some foreshadowing with youngest bro’s “wishing that he had the charm ability instead of the dead bro” and all that. But anyways that’s it for now… (Also would like to add that in the earlier chapters they were calling Luciana the Magician of Yggdrasil… might be related to what’s going on now? Who knows…) (I hope that all made sense LMAO)
I'm not able to follow this last chapter can someone explain it to me like I'm 5?