Mythic Casting [one-action] Feat 10Uncommon Mythic Spellshape Source War of Immortals pg. 84
You can infuse mythic power directly into your spells to make them exceptionally potent. Spend a
Mythic Point; if the next action you use is to
Cast a Spell, use mythic proficiency to determine your
spell attack rolls and save DC for that spell.
Traits
Uncommon: Something of uncommon rarity requires special training or comes from a particular culture or part of the world. Some character choices give access to uncommon options, and the GM can choose to allow access for anyone. Less is known about uncommon creatures than common creatures. They typically can't be summoned. The DC of Recall Knowledge checks related to these creature is increased by 2.
Mythic: Options with this trait grant or utilize mythic power. Feats with the mythic trait can only be taken by mythic characters, who are typically characters with a mythic Calling.
Monsters with the mythic trait have access to a pool of Mythic Points and are particularly strong for creatures of their level. Many mythic monsters are either resistant or entirely immune to attacks from non-mythic creatures and weapons.
Spells with the mythic trait require the expenditure of a Mythic Point in order to be cast, and items with the mythic trait require the expenditure of a Mythic Point in order to use their activated abilities.
Weapons with the mythic trait overcome the resistances and immunities of mythic monsters.
Spellshape: Actions with the spellshape trait tweak the properties of your spells. You must use a spellshape action directly before casting the spell you want to alter. If you use any action (including free actions and reactions) other than casting a spell directly after, you waste the benefits of the spellshape action. The benefit is also lost if your turn ends before you cast the spell. Any additional effects added by a spellshape action are part of the spell's effect, not of the spellshape action itself.