On a multiplayer server, the ability to kill everything one shot and take no damage is stupidly overpowered and leads to trolling, as well as completely taking the challenge out of the game. I propose that the quantum sword only do 20 damage but phase the entity out of reality for a second upon hit. The armor should only reduce damage up to 90% at protection 4 and perhaps phase the attacker's weapon out of reality for a second, as otherwise the player becomes immortal.

The whole point is to make the armor and the sword broken. If you don't want that, feel free to disable it.

How do I do that?