Dual-Edge Artifact - Abilities?

[Lazaryus]

I want to make a double-edged sword artifact called the Dual-Edge, which starts off as two halves called the Red-Edge and the Blue-Edge, which both function as Longsword artifacts. Basically, a very long time ago, a human created the Red-Edge by sacrificing his physical body, then, in the Plane of Souls, he created the Blue-Edge by sacrificing his soul. Enraged by this man's hubris, the gods wiped the man's name and his creation methods from all recollection.

Here are the abilities that I want these artifacts to have:
[list]

Some way for the Red-Edge and Blue-Edge to fuse together, becoming the Dual-Edge

The Dual-Edge allowing its wielder to reshape the reality of both the Material Plane and the Plane of Souls to their vision at the cost of the Dual-Edge and its components being wiped from existence

The Red-Edge and Blue-Edge having different abilities from each other, but generally having Dominion in their respective planes

My plan is to have the Dual-Edge and its components to be the primary macguffin of the back half of my campaign, which I split into two subcampaigns, both with their own party, and will merge them for the final session. Any suggestions?

[Shiroi]

I'd say give each one a limited wish only to emulate spells, once per day and only within the realm they control. When merged, they grant a fabled "Greater Miracle" but be careful to warn the players that they'll lose the weapon when they do that so they don't waste it. Whatever realm you use this ability on, the other one is the one that vanishes permanently.

The red one is a +5 keen blade that functions as an immovable rod and grants flying while on the material plane.

The blue one is a +5 ghost touch blade that gives dimension door at will while on the spirit plane.

Adjust power level up and down a bit for your expectations, but this should make them more than nasty enough to be sure they keep them around.

[The Sideromancer]

I would consider borrowing the power scaling from the Sword of the Planes, applied so they are at max in their domain.

[Lazaryus]

The Dual-Edge, as well as the Red-Edge and Blue-Edge, will all be destroyed when they use the "Greater Miracle".

How about the Blue-Edge being a +5 ghost touch Longsword that targets Touch AC and deals better damage (either 1d12 normal damage or inflicting permanent negative levels) at the cost of only being able to damage creatures and objects that have a soul (mock souls and soul shards count as proper souls for this purpose)?

[Wolfe Mechane]

Very cool. Do 1d12 damage

Make the red one vampiric or blood frenzied,gaining bane against individual creatures it has damaged before

[Lazaryus]

Alright. Thanks.

Any more suggestions?

[Anguish]

Once per year the wielder may grant four individuals of their choice one mythic tier.

That way not just one party member gets to have something awesome. 'Cuz otherwise you've got three players who get... nothing.

[Lazaryus]

Thanks, Anguish. I'll go with that.

When I said that the "Greater Miracle" can reshape the reality of both planes, it can also rewrite history and even the fundamental rules of the planes.

[Loxsis Bale]

Dotting.

[Loxsis Bale]

If the blue one directly harms souls, the red one could let you summon creatures that the sword has slain.

[Lazaryus]

Bump.

[J4RH34D]

I would think about granting each blade some aspect of control over its realm.
So the Blue blade would allow you to fly, and possibly act as something like a lyre of building. Allow people with the blue blade to change the physical world, so that it is an artifact in it's own right.
Allow the Red blade to cast geas or dominate monster or the like.

Perhaps have each blade allow only minor access to the abilities unless the wielder actually sacrifices the corresponding ability scores,

So allow the red and the blue to do what is explained above, but say, if the wielder of the blue blade sacrifices 1-2 of every physical ability score they can do something incredible. Like completely reshape the landscape within a 100 mile radius.

The wielder of the red can sacrifice mental ability scores to do something like cast a geas on an entire city, or some mass manipulation of souls.

When they are combined you can completely reshape reality to your wim, but you have to sacrifice all your ability points.

The important thing here is that it is not ability damage or anything like that. Your base ability score becomes less. So if you had STR 12 and you use the blue blade you now actually have a STR of 10.

[Shiroi]

You could go with a paradox. The red one only exists in the physical world and only affects the spiritual world, and vice versa.

Now you have to figure out how to coordinate overlapping the areas of effect, being in two places at once to get the right changes. The party needs to find a way (blink spell for instance) to have someone translating between realms and showing people where to use it. Lining them up in the same exact position forms a blade which exists in both realms at the same time and alters both, they can no longer be separated and can no longer be moved from this location so once they're used it's basically done for since you can't take them anywhere else.

This makes them almost useless as weapons, but very powerful as artifacts and mcguffins.