I think the seven moons killed Ritsuka's fighter by accident while trying to kill Seimei. I think Seimei is totally obsessed with Ritsuka, I think he wants Ritsuka to himself and if he finds Ritsuka's fighter he can train them without them enrolling into the school for sacrifices and fighters and eventually control Ritsuka and his fighter relationship. I also think Soubi's teacher is also obsessed with Soubi and even though he gave Soubi to Seimei he regretted it and tried to manipulate the seven moons to go after Seimei and kill him to get Soubi back. Mental illness runs in Ritsuka and Seimei's family so after constantly being attacked he would take his retaliation to the extreme ,like having moonless raped,. And I don't think he just left Ritsuka to suffer abuse my his mother. I think the seven moons might have hurt Seimei enough to make him go into hiding. On the subject of beloved I think Nisei hates Ritsuka with a passion and if he was ordered to watch and make sure Ritsuka does not die he I believe he would follow the bare minimum needed and even might have found a loophole to feel the orders. Nisei tries to get Ritsuka killed by the mom( if you think about it Ritsuka is #1 in Seimei's heart,even if it is in a extremely twisted way, and in the all the pairs are supposed to be in the most important to each other (bloodless doesn't count cause the girl was a blank that replaced the original bloodless girl). Sorry for that side comment). But yeah Soubi's teacher is manipulating everything and Seimei was forced to be the bad guy. I also think Ritsuka will get Soubi back by overwriting beloved's name because of his and Soubi's special bond leading to a breakthrough insight on blank fighters .I think blank fighters are supposed to be special and not assigned, while others are predestined and can't choose their sacrifice/fighters while blanks get (should've) to choose their sacrifices, however this was mistaken as a defect or as something bad.
I think the seven moons killed Ritsuka's fighter by accident while trying to kill Seimei. I think Seimei is totally obsessed with Ritsuka, I think he wants Ritsuka to himself and if he finds Ritsuka's fighter he can train them without them enrolling into the school for sacrifices and fighters and eventually control Ritsuka and his fighter relationship. I also think Soubi's teacher is also obsessed with Soubi and even though he gave Soubi to Seimei he regretted it and tried to manipulate the seven moons to go after Seimei and kill him to get Soubi back. Mental illness runs in Ritsuka and Seimei's family so after constantly being attacked he would take his retaliation to the extreme ,like having moonless raped,. And I don't think he just left Ritsuka to suffer abuse my his mother. I think the seven moons might have hurt Seimei enough to make him go into hiding. On the subject of beloved I think Nisei hates Ritsuka with a passion and if he was ordered to watch and make sure Ritsuka does not die he I believe he would follow the bare minimum needed and even might have found a loophole to feel the orders. Nisei tries to get Ritsuka killed by the mom( if you think about it Ritsuka is #1 in Seimei's heart,even if it is in a extremely twisted way, and in the all the pairs are supposed to be in the most important to each other (bloodless doesn't count cause the girl was a blank that replaced the original bloodless girl). Sorry for that side comment). But yeah Soubi's teacher is manipulating everything and Seimei was forced to be the bad guy. I also think Ritsuka will get Soubi back by overwriting beloved's name because of his and Soubi's special bond leading to a breakthrough insight on blank fighters .I think blank fighters are supposed to be special and not assigned, while others are predestined and can't choose their sacrifice/fighters while blanks get (should've) to choose their sacrifices, however this was mistaken as a defect or as something bad.