The dagger "Silence of the Dead" and the whip of the vampire snake are absurdly powerful artifacts. They could be heavily nerfed and still be among the best weapons in the game, so that's what I suggest doing:

Whip of the vampire snake
The whip increases in power rapidly, and can get up to or beyond (+18, 5d3+27) {Dx+43} (+43 spd). Factoring in the dexterity bonus to damage, this whip has as much base damage as axe of the minotaur emperor and gives about 2.5x the dexterity and speed bonuses of ring of the master cat. I suggest removing the dexterity blood scaling entirely (see also 5866), reducing the maximum speed bonus to about a third of what it is currently, and reducing the maximum damage bonus to around two thirds of what it is currently. Maxing out at around (+18, 5d3+18) {Dx+7} (+15 spd) would make it an incredibly good weapon, but not quite as game-breaking.

Silence of the Dead
The dagger slays humanoids, grants a ton of positive intrinsics, increases in power rapidly, and can get up to or beyond (+27, 4d4+26) {Dx+25}. The dagger does significantly more damage than the next-strongest humanoid slaying weapon, and offers massive bonuses with no drawback. I suggest completely removing the blood scaling from this weapon, as it has enough good things going for it without that. At (+6, 4d4+6) {Dx+9}, it would do comparable melee damage to other humanoid-slaying weapons, and its use as a returning missile wouldn't be so overshadowed by its melee bonuses.