Using Epic Spells to create Demon Lords/Archfey/Abominations, etc?

[Schattenbach]

I'm curious about what pitfalls might be involved when it comes to attempting to create particulary powerful custom entities like Demon Lords, Archfey, Abominations or Great Spirits and such.

Are there some things to take note of to avoid making them subject to dispell-related stuff?
Or some things that would need to be taken into account that would otherwise hinder the creation of custom entities (or well ... custom races in general) through epic spells?
There is nothing stated in the epic spell seeds that would prevent the creation of Abominations (which are, at least on paper, Divine Rank 0), did I understand that right?
What factors to take into account during the creation process (like in what way to apply the epic spell seeds) to avoid to increasing the spellcraft dc in some unnecessary/wasteful way?

Also ... what kind of (already existing) supernatural or extraordinary capabilities would be excellent to put on these kind of creatures?

Aside from these questions some other question (as at least some creators would have some interest in doing that, I guess) I've been curious about ...
Is it possible to grant some entity some superior version of True Mind Switch (that allows each creature access to the others supernatural and spell-like abilities or, alternatively, simply makes both creator and creature truly switch body, capabilities, ecetera, if that works out as intended as well) or something along these lines, combined with some means to compel it to use that on its creator.

[atemu1234]

With epic spells, one can do legitimately about anything. It really can't be parsed into 'Can it?" with an open-ended system like epic spellcasting, and moreso should be put into cases of "Should it?"

In the end you're better off leaving things like this to DM fiat.

[Zale]

I decided to make my attempt at creating an Arch-Fey using Epic Spellcasting. While that attempt is still ongoing, I thought I'd share some issues I've run into so far:

The rules I've seen don't appear to specify what the default array used for newly created creatures is. None of the seeds involved specify, nor does the example spell Origin of the Species.

There's a couple of different rulings I could see applied here; depending on which one gets used, your artificial Demon Lords and Arch-Fey are probably going to have lower ability scores than their naturally occurring fellows.

For example, if they start with, say, the elite array, then the best you can do is give them inherent bonuses to attributes, which cap a +5. That's significantly lower than you would expect. This also applies if you treat them as if they had the abilities of an animated, awakened object.

On the other claw, if you treat them as if they had all abilities as non-abilities, then you could use the fortify seed to buy up their attributes to as high as you can bear to afford.

I'm personally erring towards the second; having them start with non-abilities that are bought up, but that's just something I'm doing. I'm sure other people wouldn't; there very well might already be preexisting rulings about this, but considering it's Epic Spellcasting, I really doubt it.

There's also no rules to dictate what type a newly made creature will be, so I'm assuming that it's a freebie.

Other thoughts:

The main way people cheese Epic Spells is by abusing the additional participates modifier. The archetypal example is chain gating solars.

So this spell is probably going to end up being on the scale of a national project. Build-A-God, brought to you by your local epic spellcaster.

[Bad Wolf]

Mechanically? You can do pretty much anything.

Roleplaying wise? Thousands/millions of pure souls twisted and merged into a creature of pure evil. Also as a general rule of thumb, creating anything significantly more powerful than you is guaranteed to bite you in the ass.