I think it's geared more toward teenagers and young adults but I'll let @Wes Al-Dhaher answer. Will report back inshaAllah after I get my copy.

Good question. Brotherhood of the Wolf is dark fantasy so yes, there’s blood and fear, and the themes are serious. The tone itself is pulpy and action-adventure and not grim for its own sake. If your kids already play mainstream games, for example, they’ve likely seen more intense material, tbh. But if you’re strict about what kind of violence or scary moments they see, read it first and decide for yourself. One scholar who reviewed it told me: “Your audience will inevitably become younger since your gore is more kosher than others.” I think that sums it up pretty well.