Arrows of Disenchantment?

[Grotug]

To counteract their being too overpowered they could be generated in smaller stacks than other arrows (say a typical stack size between like 4 and 15 arrows). In addition to doing normal damage, arrows of Disenchantment would have the chance to disenchant the target monster's AC and dice attack. AC would have a much higher chance of being disenchanted than damage dice.

Another way to counteract their being overpowered is to give disenchantment resistance to certain monsters.

[wobbly]

There's already a disenchantment effect from the necromancer spell, which effects casters. If you were adding disenchantment arrows you'd probably want to keep it consistent.