Magic Item: The Ring of Negation

I have neither the problem of feeling bad about fucking up my players nor the problem of giving them too much too early; rather my problem is that I give too little too late. 

Kid Icarus has been running his own campaign for nearly a year now. We talk shop quite a bit and one of the problems that he has discussed with me off and on has been that his players have way too much magical shit and are walking over his monsters.

Now both of us hold with the Dungeon Master's Guide that . . .

When things get unbalanced, you need to fix them either in game or out-of-game, depending on the situation and the involved players’ personalities. Unbalanced character abilities or items are best handled in-game . . . (DMG pg. 14)

In my experience Kid Icarus has a terrible time dealing with these sort of issues in game. Usually what he does is labor under the players abuse until such time as they get sufficient level to where he can actually smite them without feeling guilty. I have neither the problem of feeling bad about fucking up my players nor the problem of giving them too much too early; rather my problem is that I give too little too late. 

Anyway, my solution to the problem of having too much magical gear on my players is to create an item that can address the issue in short order: a cursed item. 

Of course I like my magical gear to have a nasty side.

The Narrative

It was in the fall of '07 that the Dwarven Lord Luca watched as Holdfast burned. The goblins of the Eight Shores had swept through the valley of man during the night and slain every man, woman, and child. They swarmed even now over the valleys and up the sides of Krak Stormwind like a writhing mass of vermin. Within their ranks were mighty necromancers and shamans who tore the very fabric of reality with their foul magics and corrupted the earth with their steps.

It was Lord Luca who commissioned the Ring of Negation and the seven Rune Lords of Krak Stormwind who bound the soul of the foul beholder, Necros, within in it; sealing his soul forever with their ancient runes of power. And it was brave Sir Lawrence who strode into the writhing mass and gave up his life to end the foul magics of the swarming horde.

The Game Mechanics

The Ring of Negation causes an antimagic field to radiate 80 ft. out from the wearer. This effect cannot be canceled with anything less than a limited wish spell as the effect is created by the bound beholder, Necros. In addition the ring has been cursed by Necros' presence. Without some way to suppress the magical effects of the ring it will bind itself to the user after twenty-four hours of cumulative use, at which time Necros will begin to attempt to switch his soul's place with that of the bearer (Will DC 23 to resist).