@RaineSora25 It's very simple, first you need 34,500 KP and spend all the KP because it was a key to weaken the Beast III/R, to get KP it is very necessary to complete all the Wanted Quests that are spread across the map.
Well it was quite simple, taking down the Beast III/R, despite me having 2 Alter Egos and no Moon Cancer, I used Bazett, Miyu, Elizabeth Mecha, Angra Mainyu and Kama, but I used BB Summer as Support.
Because when I research the weakness of Beast III/R, I can find out which classes are effective against Beast III/R, a few months before the month of February.
1 week after I completed the SERAPH Main Interlude in February, I decided to get Meltryllis and Passionlip, because I had a feeling of wanting to get Meltryllis, because of what happened before finding in Custense of SERAPH, Passionlip's was because of the cuteness, that I can hardly even look at her cuteness.
I only used Kama and Angra Mainyu because of the Bonds, luckily Kama was the only one who managed to take down the Beast III/R, because the Beast III/R's life is at 30,000, so I took the opportunity to use the last Command Spell to have the Noble Phantasm at 100%, It was like using the Samsara Kama as a finishing move against Beast III/R.
Now that you have completed SERAPH, you now have BB, I don't know if you have just completed Encore because there are ascension materials for BB, and now you have access to the Ōoku Main Interlude, because you needed to complete Lostbelt 3 and the SERAPH Main Interlude.