Champions of the Titan's Eye
The ritual is an open-ended method to transfer and form energy through planes, where one plane must be the Material Plane and one plane must be an Aligned plane, such as Mechanus (LN) or the Abyss (CE).
This could be nearly anything. A powerful demon could channel energy from the material plane directly into himself in order to gain godlike power. A lawful group could channel energy from Mechanus to make the material plane more lawful and ordered. A greedy wizard could create a powerful artifact. A group of angels-turned-mortal could channel energy from the Upper Planes to restore their angelic forms and, perhaps, have the power to confront their accusers.
There are, of course, a variety of catches.
There are four main “active” components: An (aligned) incarnum component, two other “magical” components (two of arcane/divine/psionic, no doubling up), and a general “shaping” component. These components must involve mortals, located on the material plane, actually performing the ritual via these spell-like, psi-like, and supernatural abilities. The characters must also know how to perform these abilities, which our heroes already know, but others may or may not.
There are also four Elemental Components: Fire, Water, Earth, and Wind. They are hard to acquire, highly useful, and they’re expended during the use of the ritual. They’re discussed in more detail in the link above.
The last component is a sacrifice from the active participants at the start of the ritual: 2d6 ability burn to their highest ability score, irresistible.
Depends on how complicated the ritual is, and how risky you are. You could just replicate Minor Creation in about the same time it would take to cast with little-to-no complications, but that would be a waste of time. If you want to channel all the energy of the material plane into a particular demon, and you don’t want to screw it up, it might take days/weeks, and you still might screw it up.
Rituals can fail in catastrophe, or at least have unintended consequences. The more complicated and large-scale the ritual is, the harder it is to control. Being more powerful (roughly CL/ML with conditional modifiers for spell/psi components, higher of will or fortitude save with conditional modifiers for shaping component) helps contain more powerful energies. Being more skilled (roughly Spellcraft/Psicraft for spell/psi components, Concentration or pure CON check for shaping component) helps shape more complicated rituals into exactly what you want. Other ways to help control large-scale, complicated rituals are as follows:
- Increasing the time taken to complete the ritual
- Having fate be with you (i.e. spending fate points)
- Depending on the ritual, complementary components may be used to enhance the ritual. Example: If the ritual is creating a Good being using upper planar energy, a Magic Circle against Good might contain the energies.
- Depending on the ritual, certain areas might make it easier, or more “natural” to complete in (K: Planes and K: Arcana help here). Example: If you’re turning yourself into a world tree via the energies of Arborea, being in a natural, peaceful environment might help during the ritual.
- More things could work, but I’m reaching a blank and a lot of it is ritual-dependent.