First of all, biggest flaw in your story is that there's no backstory on anything. When I read it for the first time I thought I had missed 4 chapters before getting to this moment. The only thing that separates that gives us some insight to the storryy is we get is "A thousand years ago".
Your story sounded more like a fairy tale than a fictional story, and your starting sentence didn't help much to fix that either. In fairy tales we get little to no backstory, which is where you are headed right now. Only problem is you get too creative, and there's too much fantasy in there.
There's no world setting in your story. How would I know what "Ignatus" looks like if the author never gave any detail to how the city or country is.
If you're going for a fictional story and not a fairy tail I think you should give the readers more backstory, give them a setting, and try to explain what is going on more, because that's what a fictional story is. explain, explain, explain... You get the point.
Thirdly, how do you even hide mana, and spread it. Firstly you make it sound like it's a solid object, but then it's also able to be spread? I don't understand. I know you could be scratching your head and think, "this guy doesn't understand that this is a fictional story", but even they make sense, and so should yours. You can't just say everything that happens in the story is because the world is magical, there should be a limit to what can happen in it.
Lastly, I'm pretty sure you already know, but the story isn't finished, and there is no end.

Additional thoughts: Sounds like a good story, but it needs a lot of work. In the story you mentioned the mages, but you never said that they had conflicts with them until then. Maybe think of something more epic for the end, and give us a war between the witches and mages that ends in destroying Ignatus, so they are forced to go on another land, where they will discover more interesting stuff. Think two steps ahead. Also I think that "Queen's book" sounds better than "Witch's book".