We started part 5 volume 8 with a prologue following Justus. We saw his perspective as Letizia returned his name swearing stone and was told to go. We saw how Justus and Eckhart were able to escape Ahrensbach and make it to Ehrenfest's tea party room at the Royal Academy. There we witnessed Eckhart and Justus's loss of hope and their conviction to follow their lord in death after exacting revenge on the Ahrensbach archducal family. However after meeting with Sylvester and learning of Rozemyne's plan to rescue Ferdinand, their hope is restored. They promise to save Ferdinand no matter what.
In the following chapter we see Rozemyne gathering her retainers to inform them of her impending invasion of Ahrensbach to steal their foundation. She directs various tasks for her retainers to complete and decides who will join her and who will stay in support of Ehrenfest. Rozemyne's own preparations include copying and pasting maps and magic circles from her Grutrissheit. A reunion with Justus and Eckhart occurs upon their arrival after sixth bell.
Hartmut is happy to extol the miracles of Rozemyne's growth to an inquisitive Justus as Rozemyne and Eckhart eat dinner and exchange information. Justus mentions that Ferdinand had a message for Rozemyne: "I entrust Eckhart, Justus, and Lasfam to you. Stay in Ehrenfest and do nothing at all. Upon my death, everything I own will become yours. And as promised, both Ehrenfest and Yurgenschmidt will be saved." Rozemyne refuses Ferdinand's proposition and vows to rescue him regardless. Justus convinces Rozemyne to accept Ferdinand's name to envelop him with her mana thus granting more time before he is completely drained. With Justus's assistance Rozemyne creates a name-stone-enveloping box, puts Quinta's name stone inside, turns it into a cocoon with her mana, and gives Ferdinand the order to live.
The book's cover art has some plot spoilers, but there are still lots of predictions to make. Will Rozemyne's retainers learn the truth about her obtaining the wisdom of Mestionora? What role will Hannelore play? How will the Ahrensbach nobility react to the invasion? What will happen to the Lanzenave envoys? Will Rozemyne encounter resistance or will Dunkelfelger provide enough of a distraction? What will the magic circles she copied from the Grutrissheit do? How will Ferdinand react to being reunited with Rozemyne?
Yeah, that's what Rozemyne thought anyway:
I’d already connected the dots. I didn’t know how, but Ferdinand must have realized that we each owned part of the Book of Mestionora and that his death would make my book complete. - Rozemyne
Though I don't know how Ferdinand would know about how the split Grutrissheit would work, or even if he knew about it when he wrote that message (which he had to have prepared in advance of the incident). Erwaermen said Rozemyne needs his feystone, which kinda contradicts Rozemyne's interpretation of Ferdinand's message.
I was thinking the same thing. The only way I could see it working is that since the wisdom of Mestionora contains the knowledge of deceased large mana users such as zents and aubs that Ferdinand's knowledge would be added upon his death. I'm not sure how Rozemyne would be able to update her Grutrissheit with that additional knowledge or if it would just show up.