I never see this come up, Otherworld by Tad Williams? One of my absolute favorites. Intense series but carries itself so perfectly.

I haven't read this since I was young but I've read it more than once and it didn't suffer. Intense to my limit I'd say so that means nothing to you but I'd consider this above the median for intense depictions. It's spread out over thousands of pages so it makes sense, it's a mature work. I know I'm not the only one who understands my clumsy explanation.