Help with Epic spell, please?

[Aesmael]

Any mistakes or possible improvements to be made to these? The underlined factors in particular are ones I am uncertain about including. Or do epic spells belong in the Rules forum?

I plan on using this spell (or power) as the objective of an adventure for my players and want to get it right, even though they can't cast it.

Gloom of Githzerai
Conjuration (Calling)
Spellcraft DC: 100
Components: V, S
Casting Time: 10 minutes
Range: 75 feet
Target: One called creature
Duration: Permanent until dismissed
Saving Throw: Will negates
Spell Resistance: Yes
To Develop: Seeds: Summon +14 Factors: Summon Monstrous Humanoid instead of Outsider +10, Increase CR by 23 +46, Summon unique individual +60, Creature is called rather than summoned ad hoc +10, Scribe Spell x2 Mitigating factors: Burn 5,000 XP -50, Increase casting time to 10 minutes -18
This spell was crafted by Liritiza’I as a weapon of last resort to defend against the Empire’s enemies. Unfortunately she failed to anticipate the true danger and the spell remains unused, scribed on the preserved corpse of a faceless elf maiden beneath Lake Mor. When cast, this spell conjures up the Gloom of Githzerai, a servant of Murder. This is a very dangerous thing to do, as the Gloom is free to act as it wishes and nor can it be dismissed until it chooses to leave.

OR

Gloom of Githzerai
Psychoportation (Calling)
Psicraft DC: 100
Display: Visual
Manifesting Time: 10 minutes
Range: 75 feet
Target: One called creature
Duration: Permanent until dismissed
Saving Throw: Will negates
Power Resistance: Yes
To Develop: Seeds: Summon +14 Factors: Summon Monstrous Humanoid instead of Outsider +10, Increase CR by 23 +46, Summon unique individual +60, Creature is called rather than summoned ad hoc +10, Scribe x2 Mitigating factors: Burn 5,000 XP -50, Increase casting time to 10 minutes -18
This power was crafted by Liritiza’I as a weapon of last resort to defend against the Empire’s enemies. Unfortunately she failed to anticipate the true danger and the power remains unused, scribed on the preserved corpse of a faceless elf maiden beneath Lake Mor. When cast, this power conjures up the Gloom of Githzerai, a servant of Murder. This is a very dangerous thing to do, as the Gloom is free to act as it wishes and nor can it be dismissed until it chooses to leave.
For Liritiza’I this power was within her primary discipline. When manifested by her reduce the DC by a further 5.

 

[tjoneslo]

Gloom of Githzerai
Conjuration (Calling)
Spellcraft DC: 16
Components: V, S
Casting Time: 10 minutes
Range: 75 feet
Target: One called creature
Duration: Permanent until dismissed
Saving Throw: Will negates
Spell Resistance: Yes
To Develop: Seeds: Summon +14 Factors: Change type to Monstrous Humanoid +10, Increase CR by 23 +46,

Changing the type of creature to a Monstrous Humanoid is a Transform seed, which is DC +21.

What powers are you giving the creature to give it a +23 CR? The creature can not have more levels/HD than the caster, and any over 15 would be DC +2 for each one. And each ability is a +10 DC to the spell.

You've also missed the scribe spell casting requirement which doubles the DC.

 

[Aesmael]

Changing the type of creature to a Monstrous Humanoid is a Transform seed, which is DC +21.

What powers are you giving the creature to give it a +23 CR? The creature can not have more levels/HD than the caster, and any over 15 would be DC +2 for each one. And each ability is a +10 DC to the spell.

Ah, misunderstanding/miscommunication. The Summon seed specifically summons Outsiders, to summon a different type of creature of CR 2 adds 10 to the DC. Then you need to add 2 more to the DC for each CR higher than 2 that the creature you summon is. A Gloom is a specific type of epic monster and in this setting there is one and only one of them for each kind of creature (rather than all having human dread weapons), thus the unique creature category.
Will edit to fix this.

You've also missed the scribe spell casting requirement which doubles the DC.

Aha!