Invoke the Crimson Oath
Brandishing your weapon and shouting the final line of the Crimson Oath, you unleash a blast of destructive ruby energy. You must be wielding a melee weapon, and you perform this spell's somatic component by swinging the weapon in a downward arc. You deal normal melee damage for your weapon, including all appropriate bonuses, penalties, modifiers, and properties, to each creature in the spell's area; they must each attempt a basic Fortitude save. A creature that critically fails this save also suffers any additional effect you would normally inflict with your weapon on a critical hit; if the creature that critically fails its save is also immune to critical hits, it merely fails the save instead.
You can convert all the physical damage from this spell into vitality damage against all undead creatures in the area.
Traits
An action with this trait requires a degree of mental concentration and discipline.
Focus spells are a special type of spell attained directly from a branch of study, from a deity, or from another specific source. You can learn focus spells only through special class features or feats, rather than choosing them from a spell list. Furthermore, you cast focus spells using a special pool of Focus Points—you can't prepare a focus spell in a spell slot or use your spell slots to cast focus spells; similarly, you can't spend your Focus Points to cast spells that aren't focus spells.
You must physically manipulate an item or make gestures to use an action with this trait. Creatures without a suitable appendage can't perform actions with this trait. Manipulate actions often trigger reactions.