I think one of the best parts about this manga is how well the past ties into the present. It's just how everything ties together so well that makes this such an enjoyable read. The readers could tell how much Frieren hated demons even before the reveal that they killed her entire village just...
Well now we know why he killed the MC in their previous life even if it seemed like he somewhat liked her. Once the ML inherited the Heaven Destroyer, he lost all his emotions, and in his eyes, the MC turned from an endearing woman always chasing after him to a nuisance who always hinders him.