This is the song.

Nox: I'm you and our brother Matin: What????

11 years late let’s go > Cool lady with lightning for hair (Sigma) tries to create a perfect human that can get to the truth of Ristaccia (red crystal in everyone’s swords) > L’erisia (red haired girl) did not like that. > Once Lien, the culmination of this perfect human project and a nerd (math genius) arrives on some ruins to do just that, Shamshir (lady with a feather on her veil and a dancer outfit) is led there to kill him by L’erisia. Lien takes the L. > Sike bitch, it’s not over. Project continues which results in the heir of a kingdom that worships the sword Trisagion. > Trisagion is a sword with the funky red crystal btw. So it’s all L’erisia’s plan in a way. > Matin and Nox are born. L’erisia, somewhat scared shitless that there will be a second Lien, decides to make everything in her power so that this doesn’t happen. So she basically gives Matin Trisagion and Nox is given Tyrfing. > Since Matin is the one who is liked by the sword Trisagion (the one this kingdom worships), Nox is yeeted out of the palace. Any mention of the “legitimate heir” (Nox) is Alt+F4’d. > L’erisia’s plan works since now Matin and Nox are separated completely and thus can’t become a superhuman like Lien. > Nox grows in the rebellion hating this kingdom since they’re assholes, while Matin is too Pure For This World ™ to notice she’s being 100% manipulated by the adults. > Nox and Matin actually meet, but they don’t know they’re siblings. Matin cosplays as someone called Lucis and they have a nice chat together. > Since L’Erisia just does NOT want them to be one again, she basically drives Nox mad and it gets even worse when Matin reveals herself to be Lucis during one of the biggest battles between the Rebellion and the Kingdom. That’s the extent of it for the context of this video (Ristaccia) and Blind Justice 👍🏻