The Orb of Evil - The Regalia of evil - help understanding some of it.

[Azrael9986]

The orb says it gives you several things.
15 rebuke and command levels of cleric.
+4 wisdom
it works as a rod of absorption
you are greedy over time.

So do the 15 levels worth of rebuking stack with actual cleric levels. It doesn't say it doesn't. but I am not sure because if they do that would be awesome. plus I think I could convince my DM for epic play to let me have this slot-less artifact. it would also let me control undead in epic play like most clerics have issues handling. The other two artifacts are nice but I bet I would need to share them most likely. as someone with all of them gets well rather powerful rather fast seeing as two of them are slot-less items and one is a crown.

For reference the Items are on page 122 of the book of vile darkness. Honestly as far as artifacts go these are kinda weak on their own. all three together are wicked powerful though. though the speaking only lies thing would get annoying. so I don't see the crown being all that popular. though the vile damage from all weapons is crazy powerful. only a extremely blessed location with heals can fix it.

[illyahr]

No, they don't stack. It says you can rebuke as a 15th level cleric, not that it adds to your cleric levels for rebuking. You would use whichever value is higher.

[BowStreetRunner]

No, they don't stack. It says you can rebuke as a 15th level cleric, not that it adds to your cleric levels for rebuking. You would use whichever value is higher.

As illyahr pointed out, this does not give a bonus to cleric levels, so it would not stack with existing cleric levels. However, anything that did give you a bonus would stack with the levels from the artifact if you chose to use its power. So for instance if you have 5 ranks in knowledge religion you could apply that when using the orb.

[Azrael9986]

Okay so it gives a separate ability to use rebuke undead. o-o does it have a separate pool of 3+cha mod to use rebuke undead?