The One Magic Item to rule them all...

[Vespe Ratavo]

Yup. Whipped this up for the Stuff that Someone oughta do thread. (http://www.giantitp.com/forums/showthread.php?t=31115)
The One Ring- The One Ring was created by the Dark Lord Sauron during the Second Age in order to gain dominion over the free peoples of Middle-earth. In disguise as Annatar, or "Lord of Gifts", he aided the Elven smiths of Eregion and their leader Celebrimbor, in the making of the Rings of Power. He then forged the One Ring himself in the fires of Mount Doom. Since the other Rings were extremely powerful, Sauron was obliged to place most of his native power, life force and will into it to effect his purpose. A side effect of his doing this was that as long as the Ring existed, it was impossible to remove him from the mortal plane. The risk to Sauron was that if he were to lose the Ring, he would also lose a great deal of his own power, and if the Ring were to be destroyed, perhaps even his life. The Ring may only be destroyed in the fires of Mount Doom.

Powers of the One Ring- First, wearing the Ring, even for a brief time, greatly extends ones lifespan. The Ring cannot impart immortality, but wearing it extends ones lifespan by 7d6 years. The Ring, while worn, turns the user invisible, except to Sauron and a select few of his lieutenants. The Ring grants the power to control non divine creatures (in effect, free use of Dominate Monster), however, one must make an Intelligence or Wisdom check to learn how to use this power (DC 30). The Ring also amplifies any power the user possesses. (+5 to skill checks, +2 to attack rolls) The Ring also has a large ego (Int 18, Wis 18, Cha 18, 29 ego) and always attempts to return to Sauron, and has the ability to slip out of ones possession easily. The bearer of the Ring must make a Will save to discard the Ring (DC 15, increases by one each week in the characters possession) unless the Ring wants to be discarded. The character must also make a Will Save every two weeks to avoid becoming Evil. (DC 10, rises by one each two weeks) Hobbits/Halflings have +5 on both checks.


Edit: Should be kinda obvious, but this is a major artifact.

[Eighth_Seraph]

Powers of the One Ring- First, wearing the Ring, even for a brief time, greatly extends ones lifespan. The Ring cannot impart immortality, but wearing it extends ones lifespan by 7d6 years. Eh, it was VERY strongly implied in the books and outright said in the movies that Smeagol was nigh on 500 years old. The Old Took, which is the oldest hobbit in recent history aside from Bilbo himself was only 130 years old when he died. I'd say that's a bit more than 7d6 years.
The character must also make a Will Save every two weeks to avoid becoming Evil. (DC 10, rises by one each two weeks) Hobbits/Halflings have +5 on both checks. Well, Frodo was essentially a, what, fifth level commoner, being generous? He bore the ring for a good long time (I want to say almost a year, but I don't want to go back and count days in the books) and only ever became 'evil' on the edge of Mount Doom, when he refused to toss the Ring in. Maybe granting the Ring bonus ego when in danger of destruction?

[Hyrael]

No, frodo was an aristocrat, or an expert. Nice stats, but the ring should extend lifespan far more than that, and should grant all sorts of other powers to someone who knows how to use it. the books were rather ambiguous on the powers of the ring with a skilled user, but a +10 enhancement bonus to charisma might be in order, for example.

[MeklorIlavator]

I would also have it give some stat boosts, and the invisibility should probably be changed to ethereal. Remember, in the movies(and it was implied in the books) that while wearing the ring, the world became the "wraith world" sounds like some sort of ethereal plane.

[Quietus]

I would say that the ring doesn't so much try to turn the owner evil, as flat-out attempts to take them over and FORCE them not to do whatever it is that they are doing.

As for the aging/timeline... make it slow the posessor's aging while the ring is with them. For example, perhaps every 10 years the ring is in a person's possession, they only age 1? That would mean Smeagol, having picked up the ring when he was young (maybe 15?), being 500 years old, would have only aged another 48.5 years in the time the ring was with him. Perfectly possible he could have survived 63 years, with whatever race he was being a Hobbit ancestor.

[Eighth_Seraph]

I second the move for more powers when the ring possesses a skilled user. The only way that I could possibly think to do this is to make it a Legacy item, with its basic powers being a Ring of Invisibility and Longevity. I don't own Weapon of Legacy, though, so it might be a better idea to ask someone that does. The Demented One does (He made me Teluos, Flute of the Moon and the Penumbra, both legacy items) as does Gralamin, though I'm not sure if that's still his name. Or if you have the book, Vespe, we can get crackin' on this.

[Zarincos]

and maybe something about what happens once you're ethereal? as i remember (movies, not books) every time Frodo put the ring on for more then a few seconds Sauron found him and seemed to do some sort of damage, probably subdual.

[Neek]

This is much better than Skrodo's Only Ring!

Skrodo's Only Ring

A small, innoccuous golden ring whose bearer goes back to an unwashed halfling named Skrodo. After much gambling, he was forced by the honest wisdom of a baseball bat against his kneecap to give the ring up. And from there, it passed hands. Possibly because no one wants it, except for Skrodo.

If anyone attempts to wear the ring, they are forced to make a Willpower save (DC 15, 20 vs Halflings) or be stunned by a giant flaming eye that takes up their entire field of vision for 2d4+1 rounds. While wearing the ring, the wearer is invisible. Side effects of failing the Willpower save include hoarding the bling and calling it "Precious."

So far, though, this is good. Does it confer any other bonuses? Because at the battle of the close of the 2nd Age, Sauron was made helpless only after his ring was lost; I see that it provides some bonuses, and they are not that bad either! However, what happens if a bearer looses the ring--your description doesn't account for Gollum's reaction.

[Yakk]

Use points: Every time you use a power of the ring, you accumulate one or more use points.

The One Ring can revoke any of these powers at will.

Empower Stealth: Invisibility when worn: 1 point per use, plus 1 point every 2 hours invisible.

Empower Magic: Increase DC of a spell by 5, doubles your caster level, and add up to 5 additional levels of metamagic feats to your spells at no charge. When you cast a spell, you can make a caster level check against DC (10+2*spell level) when you cast the spell -- on success, you do not lose the spell points/spells per day/etc. 1 points per use.

Empower Combat Feat: Gain +1 attack for every BaB given up to a combat feat. In addition, on every attack you can pick a "standard action" special melee option for which you have a feat, and do that as well as doing damage (such as during a whirlwind attack, or a full-attack action). Any bonus's granted by feats to moves are multiplied by 5 (ie, instead of +4 to trip, you get +20 to trip). 1 point per round.

Empower Speed: The weapons you wield are considered weapons of speed. In addition, the character can make a move action during a full-round action. 1 point per battle.

Empower Body: You can increase your Strength and Constitution by your respective Strength and Constitution bonus's. 1 point per week.

Empower Saves: +20 to saves against an attack. 1 point per use.

Empower Defence: +10 AC for a round. 1 point per use.

Empower Charisma: Increase your charisma by your charisma bonus (1 point per week), and double your skillpoints in any charisma-based skills (1 point per skill use).

Every use point makes it easier for the ring to control you. For each use point, making a save against the ring's powers is at +1 DC.

The one ring, in the possession of a warrior, makes the warrior fearsomely powerful. The one ring, in the possession of a wizard, would shake the world.

"I would use the ring to do good, but through me, it would wield a most terrible power."

In the hands of a medium-to-high-level fighter, it makes the fighter into a badass.

Suppose 20 strength, 17 con, 12 dex, 14 charisma, L 10.
They now have 25 strength, 20 con, 16 charisma. They can do a full-power-attack every round with no penalty to hit (+20 damage with a 2 H weapon). Doing a whirlwind bull's rush can be made with a total of +27 to the strength check -- knocking almost everyone back in melee range about 20 feet.

Fun eh?

[Krimm_Blackleaf]

I think it should use rules for taint, I just think it sorta suits it.

[Mewtarthio]

I second the move for more powers when the ring possesses a skilled user. The only way that I could possibly think to do this is to make it a Legacy item, with its basic powers being a Ring of Invisibility and Longevity. I don't own Weapon of Legacy, though, so it might be a better idea to ask someone that does. The Demented One does (He made me Teluos, Flute of the Moon and the Penumbra, both legacy items) as does Gralamin, though I'm not sure if that's still his name. Or if you have the book, Vespe, we can get crackin' on this.

You could try some sort of variant on the Legendary Weapon Scion (http://www.d20srd.org/srd/variant/magic/legendaryWeapons.htm) PrC. How about this "feature":

If the Scion attempts to gain a level in any class besides Scion of the One Ring, he must make a Will save (DC 15 + Scion level) or be forced to take his next level in Scion. If the Scion does not have the One Ring in his possession, he gains a +2 bonus on this save, but failure results in him losing that level permanently, as though slain and ressurrected (note that this level loss occurse after the level up: Effectively, the Scion simply does not gain a level).

[Indon]

I think the ring's powers should be heavily modified if one has arcane casting ability.

Perhaps, say, the ring has 10 ego plus 3 per caster level of the wielder, and other similarly scaling effects?

Frodo: "Man, this ring sucks. You want it, Gandalf?"
Gandalf: *runs away screaming*