Manifests hit up to 1.2k or so. And the cores are rare enough to get very little divination xp. It's not over 20k per hour. Not sure why the part about xp and drops is wrong, manifests give like 900 xp and it's even less for the others. And all that for doing 15k damage each. Just compare them to dark beasts that have 8.5k life.
Hi