EDIT: Improved Metamagic should be a Divine Ability, if you're not banning it outright (which is probably the best option, Wizards don't need three different ways of casting more powerful spells). Breaking up Improved Spell Capacity and Automatic Metamagic Capacity might be a thing. They were both good feats before you merged them. Perhaps combine Improved Spell Capacity with an ability that lets the user learn one Epic spell of the level of the slot ISC grants without paying the research cost, so you don't have the annoying problem of having to re-research your spells as you level up because they go obsolete. And there's a point to designing epic spells at levels other than "The absolute maximum that you can reliably cast" because you get a bunch of lower-level ones for free.
Twinned and Repeat spells should only be able to be applied more than once through AMC.
Final Phoenix
Colossal Magical Beast (3 VSCs)
Hit Dice: 160d20+11,040 (25,280 hp)
Initiative: +60 (+32 dex, +8 feat +20 sacred), Perfect, Sixth Sense
Speed: 300 ft., fly 2,730 ft. (perfect)
AC: 251 (-8 size, +32 Dex, +113 natural (16 hd +69 con +35 size), +83 deflection +20 sacred +1 dodge), touch 138, flat-footed 250, dodge, mobility
Base Attack/Grapple: +160/+239
Attack: Bite +299 melee (30d10+64/19-20/x2 plus 40d20 divine fire)
Attack: Ethereal Flames +299 melee transdimensional touch (240d20+340 divine fire)
Full Attack: Bite +299/+299 melee (30d10+64/19-20/x2 plus 40d20 divine fire) and 2 Claws +299/+299/+294/+289/+284 melee (20d10+21/19-20/x2 plus 40d20 divine fire) and 2 wings +299/+299 melee (8d6+21 plus 40d20 divine fire) and Tail +299 melee (8d6+21 plus 40d20 divine fire plus Perfect Prismatic Strike)
Space/Reach: 60 ft/30ft
Special Attacks: Shriek, spell-like abilities, ethereal flames
Special Qualities: Uncanny Dodge, DR 160/Epic and Evil, Immolation, Low-Light Vision x20, Planar Travel, Perfect Spell-like metamagic, SR 175, telepathy, defensive aura, darkvision 600ft, resist sonic and electricity 90, immune to fire, ageing, death effects, disintegration, polymorphing, ability damage and drain, disease, charms, poison, compulsions, paralysis, poison and petrification, Fast Heal 80, energy aura, phoenix flames
Saves: Fort: +253 Ref: +219 Will: +212
Abilities: Str 96, Dex 74, Con 148, Int 50, Wis 64, Cha 180
Skills: Omnicompetent (All Skills +163 ranks +20 Sacred + Ability Score + Synergy)
Feats: Enlarge Spell, Empower Spell, Extend Spell, Flyby Attack, Heighten Spell Improved Critical (claw), Improved Initiative, Iron Will, Maximise Spell, Improved Critical (Bite), Quicken Spell, Improved Natural Attack(bite, claw), Rapidstrike, Improved Rapistrike, Multiattack, Improved Multiattack, Improved Flight, Ability Focus (Shriek, Immolation), Transdimensional Spell, Alertness, Combat Casting, Dodge, Mobilty, Widen Spell, Split Ray
Epic Feats: Metamagic Freedom, Weapon Abatement, Automatic Metamagic Capacity x40, Automatic Metamagic Capacity x10, Improved Metamagic x2, Superior Initiative, Blinding Speed, Sixth Sense, Ethereal Vision, Improved Combat Casting, Enhance Spell, Great Charisma x12, Etheric Vision
Divine Abilities: Divine Toughness, Spell Abatement, Celerity, Heavenly Mind, Heavenly Soul, Perfect Initiative, Learned Spell Immunity, Maven, Omnicompetent, Quickness, Anyfeat, Eternal Freedom, Third Eye
Cosmic Abilities: Legendary Charisma, Legendary Constitution
Climate/Terrain: Any land
Organization: Solitary
Challenge Rating: 108
Treasure: None
Alignment: Always neutral good
Advancement: -
Shriek (Ex): Once every 1d2 rounds, a great phoenix can utter a war shriek that forces every opponent within 425 feet to succeed on a Will save (DC 205, charisma-based) or be deafened and slowed for 8 rounds, and takes 160d20 divine sonic damage (Reflex half, same DC). This is a sonic, mind-affecting effect.
Spell-Like Abilities: Always active: detect evil, greater arcane sight, holy aura, true seeing, owl's wisdom, eagle's splendour
at will - blindness, delayed blast fireball, mass eagle's splendour, greater blink, blur, colour spray, continual flame, mass cure critical wounds, dancing lights, find the path, find traps, fireball, fire seeds, fire shield, fire storm, heal, mass heal, holy word, incendiary cloud, greater invisibility, misdirection, negative energy protection, neutralise poison, mass owl's wisdom, plane shift, polymorph, prismatic sphere, prismatic spray, prismatic wall, produce flame, pyrotechnics, rainbow pattern, reincarnate, remove fear, remove curse, scorching ray, scintillating pattern, see invisibility, summon nature's ally IX, greater teleport, true seeing, veil, wall of fire
3/day: miracle
1/day: contingent true resurrection
Caster level 180th, save DC 115 + spell level
After 10 rounds of ritual and preparation: dismissal, dispel evil, dispel magic, greater dispel magic, mordenkainen's disjunction, banishment, caster level 340th, save DC 115 + spell level
Phoenix Flames (Su): A Greater Phoenix is usually wreathed in flames, although it can suppress this ability as a free action. Any creature striking it with a melee weapon takes 40d20 divine fire damage (no save), and its natural weapons deal an additional 40d20 divine fire damage. All fire damage dealt by a Greater Phoenix is considered divine fire damage.
Defensive Aura (Su): A Great Phoenix has a deflection bonus to AC equal to its charisma modifier
Immolation (Su): When it knows that death is near, once per day, a phoenix (which must be on less than half hit points) immolates itself as a full-round action. This produces a cloud of flame 850 feet high in a 425 foot foot radius spread, each creature in the area takes 320d100 divine fire damage (reflex DC 181 half, constitution-based). This action kills the original phoenix and produces a new one, fully grown and unharmed from the ashes. This new bird arrives at the end of the round. When a Final Phoenix is resurrected by its contingent true resurrection spell-like ability (but not any other ability that restores the dead), it deals 240d20 divine fire damage (reflex half, same DC) to all creatures within 425 feet.
Planar Travel (Su): A phoenix can enter and exit the Astral Plane or Ethereal Plane at will and navigate through these planes without error or risk.
Ethereal Flames (Su): A Great Phoenix's flames can harm creatures on coexistent planes, creatures on coexistent planes within the areas of its Phoenix Flames, Energy Aura or Immolation abilities take damage as if they were on the same plane as the Great Phoenix. As a standard action it make make a melee touch attack against a creature on a coexistent plane dealing 240d20 divine fire damage plus quadruple its charisma modifier.
Perfect Spell-Like Metamagic (Ex): A great phoenix can apply any of its metamagic feats to a spell-like ability without changing the action of the spell. It gains Metamagic Freedom as a bonus feat, and Automatic Metamagic Capacity equal to one quarter of its hit dice (40, in this case). Any metamagic it applies this way is considered to also Heighten the spell in question by the spell slot adjustment of the metamagic
Telepathy (Su): A great phoenix can communicate telepathically with any creature within 6000 feet that has a language. It can also speak with any avians, whether or not they have a language.
Uncanny Dodge: As the rogue feature of the same name. A Great Phoenix has an effective rogue level equal to its hit dice for purposes of flanking.
Energy Aura (Ex): All creatures within a Great Phoenix's reach suffer 16d20 divine fire damage every round (no save). While flying, the flames shed from its wings persist, and any creature that enters a square that the Great Phoenix threatened at any point during the round takes damage as if it were adjacent to the Phoenix.
Prismatic Tail (Su): A Final Phoenix has a tail that shines with all colours of the rainbow, it gains a secondary tail natural attack (appropriate for its size and virtual size) which deals extra damage as Perfect Prismatic Strike (40 damage dice in this case) on a successful hit.
Heat Haze (Ex): When in atmosphere, a Final Phoenix using its Phoenix Flames ability produces enough heat to distort the air around it. All creatures within 425 feet of a Final Phoenix gain a 20% miss chance (the phoenix itself ignores this miss chance), while the phoenix itself gains a 50% miss chance, and the air within this area is considered Burning Heat (see Sandstorm page 13). These miss-chances result from concealment.
