[@Zeroth] Thank you! And right, regarding the magic I think I understand what you're saying. I knew that the mana was coming from the environment, not the rod. But I hadn't fully worked out how the spells are related to the rod, compared to a spellbook or something similar. Maybe we can say that the rod contains some of the formula for each spell in the form of inscriptions/sigils. I suppose it would only be a small portion of the spell, given their complexity. But the amber orb also acts as an important material focus for the spells, so it's not an entirely optional element. Or whatever works for you, really. I wanted the item to be important, but I can rewrite it a bit if that doesn't ultimately make sense in this verse. 

I think making Minerva the last child of Devidas makes sense, and will help connect her with the other characters and the world. I am having a little trouble figuring out where Allan fits on the family tree. The image someone made before helped a bit though. I wouldn't mind having him be from one of the other shoots of the family. A child of Austenos or Fulya perhaps? I didn't touch much on his family history apart from saying he had a strict father. He is on the younger side of the generation, I think? Probably not the child of a mistress. His shame was due to personal failings rather than his own illegitimacy.

I'm totally down to use one of your concepts for the demon captain. Later on you could give me a brief description in PM so I can keep an eye peeled for him!