Generally during each arc the chapters start with average length then get longer as the end of the arc approach. (with my reading speed (not that fast) the first chapters take around +/-10 minutes, and the longer +/-20min with some really long ones taking +/-30min)
And yeah, something I like is that the novel is pretty straightforward, so stuff happens in the chapters. Only exception are battle were basically it's just the author trying to make the enemy looks strong only to be utterly destroyed by Anos.
But in general "normal" battles last 1 or 2 chapters, only "big/boss" battles reach 5+ chapters.