DM: "What's your Magic Resistance Adj."
Magic-User: "+10%...I'm only 9th level."
DM: "OK, so the Bone Devil has 50% vs your Charm Monster...[rolls percentile dice]...and it fails. OK, so that means the devil needs a 10 to save. I'm going to use the mammoth d20 for this roll."
[everyone is watching because this battle is so perilous for the party, ambushed as they are along a stretch of winter road they are accustomed to travel. It leads to their tower stronghold half a day's ride beyond the city. A former party member has summoned a devil and employed archers in the trees. He seeks to take their items and see them dead.]
DM: [tosses die] "WHAT!" [Immediately starts laughing]
Reactions around the table were loud and varied, but the game carried on. A different die was used [also by Artisan Dice] to re-roll the save. A 16 came up and the devil was not charmed.
I took a photo of the shattered die and sent an email to Artisan Dice in real time, during the game. They are a fantastic company and their dice are beautiful. I highly recommend them.
I have not received an answer yet to the mail, but I'm pretty sure they will make it right.
In the end, the party won; the magic-user playing a central role in the victory. Yes, Monte, if you're reading this...Mortimer Vossen is the best wizerd of all time...zzzzzz.
During the battle, Mortimer's Ring of Spell Turning came into use. This magic item is prime fodder for any AD&D detractors because, as written, it's a mess.
We, however, deciphered it as best we could and I've decided to share our chart, that tries to turn the convoluted text of the DMG p. 131 into a simple table that you can reference.
Behold, the 1st Edition Ring of Spell Turning;
When the wearer of the ring is targeted by a spell, simply roll % dice. If the spell is a damage dealer, use the first column: it will tell you what % of the rolled dmg is reflected back at the caster.
If the spell is NOT a damage dealing spell (like charm person) and if there is a saving throw, use the second column. This is the saving throw bonus applied to BOTH the wearer of the ring and the enemy caster. Thus, on a 96, the enemy caster must ALSO save vs Charm Person at NO bonus or be charmed by her own spell.
If the spell does NOT allow a saving throw, consult the last two columns. Gygax's love of one roll for many uses comes into play here. As you can see, the chart attempts to convert the complicated phrasing under "Note Regarding Ring of Spell Turning" on p. 131 into an easy cross-reference. So in the case of Power Word Kill, for example, the ring wearer rolls % dice and a result of 34 comes up (exactly the same as in the DMG example). The saving throws generated by the ring are 18 and 14 respectively. The ring wearer needs an 18 or better or he is slain (15%). The enemy caster needs a 14 or better (35%), which doesn't exactly match the DMG's 30% because I'm rounding 66% up instead of down. You are welcome to pore over the DMG version, compare and judge me a heretic if you like.
Otherwise, please accept this table as a free gift that allows you to make use of the Ring of Spell Turning as Gygax intended (without pulling your hair out and cursing).
On a final note, during our battle last night, the enemy M-U hurled a fireball at Mortimer. I erroneously allowed the spell to be turned back (RoST does not turn back AOE spells). In the aftermath of the fight the player conceded to me that he'd realized my mistake. It was a grievous one since a 94 had been rolled, and Mortimer suffered only 1 dmg after making his save. The enemy caster failed his save, took 21 dmg, which rendered him unconscious, terminated fly and fell 20' to the surface of an icy pond which cracked his skull and ended him.
Monte, if you're reading this, you'd almost certainly have gotten the hero point you wanted in reward for honesty during the battle (I've done that several times before). But your only reward now is that the ring miraculously turned a spell it shouldn't have, and all of you lived to fight another day. I don't begrudge the victory in the least.
Peace, and Happy Gaming.