Ring of Red Ruin
At the cost of one charge, this ring emits a beam of searing light towards a single target within 20m. If the target fails to dodge (the beam has a speed of 20), he suffers 1d20 HP of damage. Magical armour will reduce the damage taken by its magic bonus; nonmagical armour is ineffective.
The ring has 5 charges, which cannot be replenished, once used for the 5th and final time the ring becomes merely an expensive finely wrought gold ring mounted with an exsquisitely cut large ruby (mundane value of approximately 500 gold pieces).
The high Magi of Krarth would bestow these rings upon acolytes and promising lower level students upon completion of the third and fourth tier tests they set for them. The wicked and spiteful Magi knew exactly what they were doing, and in the hands, and indeed on the fingers of the most ambitious and merciless students the pool of prospective acolytes with the “right moral fibre” was greatly reduced and the master sorcerors were able to focus their energies on the continued instruction in the dark and deep ways of the arcane on these most promising of students.
Rings of red ruin are not unique, but to find rings with charges remaining is extremely rare, the more so since Spyte, the capital of Krarth in the days of the Magi suffered the sundering and was plunged into chaos by the primordial gods and demons the Magi tried unsuccesfully to control.