The most epicest artifact?

[Empath Negative]

What's the single most powerful artifact in D&D 3.5?

 

[the Jester]

In my campaign, it's Cleaver, the only remnant of the ancient Monty Haul days of my campaign.

Cleaver hasn't appeared since the 2e days, but in 3e terms it's something like a +27 throwing returning longsword with an additional ability to cleave incoming attacks in twain, including e.g. lightning bolts or fireballs.

Cleaver was the tool of a family of power-mad individuals who went from universe to universe enslaving gods. The Steel family.

They are long dead, but Cleaver was too potent to be destroyed. It was locked away (for all time?) by a coalition of gods.

 

[Dozen]

The Ruby Rod of Asmodeus might be a canditate. The damn thing sprouts 20d6 direct damage spells at will, makes attackers bow down for you so you can smash their skulls in, produces an antimagic field once per day, and it counts as a +6 greatclub in addition. Oh yeah, and the one who wields it becomes the ruler of the Nine Hells. Good luck getting it from him though, he has it for a reason. That is, being the single most powerful entity in existence after the Greater Deities.

 

[Sekhmet]

The Ruby Rod of Asmodeus might be a canditate. The damn thing sprouts 20d6 direct damage spells at will, makes attackers bow down for you so you can smash their skulls in, produces an antimagic field once per day, and it counts as a +6 greatclub in addition. Oh yeah, and the one who wields it becomes the ruler of the Nine Hells. Good luck getting it from him though, he has it for a reason. That is, being the single most powerful entity in existence after the Greater Deities.

He was made a deity in 4e.

 

[Dozen]

He was made a deity in 4e.

O-kay... So?

 

[Sekhmet]

[MENTION=6698275]Dozen[/MENTION]

being the single most powerful entity in existence after the Greater Deities

Well, he's a greater deity now.
I was being informative not argumentative.

Should be noted that none of of the deities, demigods, or unique devils/demons are the strongest things in existence, the Devastation Scorpion or Devastation Beetle can kill most of them without any real problems; and it's just a mindless vermin.

 

[Advilaar]

Many Artifacts are situationally epic.

For instance, if you are facing psionic foes, there is The Annulus. It automatically makes powers harder to manifest. Dimension anchors in a radius. Gives a daily nuke power.

Once per year it can utterly destroy any psionic being in a 100 ft radius, even a god. It can also destroy psionic artifacts. Of course things of that nature destroy the Annulus.

 

[grodog]

I would probably go with The Codex of the Infinite Planes or the Crook of Rao, myself, but you can always change up an artifact or relic to make them more or less powerful than as written.

The Origins of Greyhawk Artifacts and Relics details a list of artifacts and relics from the Greyhawk setting, many of which originally appeared in the 1e DMG and 2e Book of Artifacts. Might be useful for ideas
(This is basically the same list Erik Mona and I published in Dragon 299's "All Oerth's Artifacts" (and the material cut from that article before publication appears @ Canonfire! - Artifacts of Oerth Article: B-Sides and Errata).

 

[Celebrim]

What's the single most powerful artifact in D&D 3.5?

I don't know about 3e, but if they translate faithfully from 1e, likely candidates are:

Heward's Mystical Organ
The Machine of Lum the Mad
A full set of The Teeth of Dahlver-Nar

 

[RUMBLETiGER]

The Head of Vecna.