Ring of Tzakarath (3.5e Equipment)
From D&D Wiki
The Ring of Tzakarath is the final piece in the trifecta of cursed artifacts created by Tzakarath. He keeps it always on his person, and upon his death, his soul and divine spark will enter into it, preserving it indefinitely. The ring is indestructible save by one means - it must be thrown into the Void that lies outside the multiverse, where it will disintegrate in the flood of chaos that is it. Other than that, it is completely indestructible by any means, and cannot be damaged in any way.
A plain silver ring, with gold writing upon it: "He who returns this to my Crown and Book shall be given an eternal reward". The writing is understandable, no matter what language you use.
The Ring of Tzakarath enables the wielder to cast spells as though he were a 9th level Wizard, regardless of whether the caster could or could not cast them beforehand. All spells cast using it have the evil descriptor, even if they did not have it originally. It is not used up by this.
The Ring causes the wielder pain when he performs good deeds and pleasure when he performs evil ones, enough to cause a change of alignment. It also implants an obsession in the wielder's mind to find the Book and Crown of Tzakarath.
When the wielder reads from the Book of Tzakarath and wears the Crown, Tzakarath possesses him and flees back to his home plane, scheming and plotting anew.