When you choose this archetype at 3rd level, you learn to master forbidden alchemical formulas—known as mutagens—that can temporarily alter your mental and physical abilities.
As a bonus action, you consume a mutagen, whose effects and side effects last until you finish a short or long rest unless otherwise specified. While one or more mutagens are affecting you, you can use an action to focus and flush all mutagens from your system, ending their effects and side effects.
Mutagens are designed for the specific biology of the character who concocted them, and your mutagens have no effect on other creatures. They are also unstable by nature, losing their potency over time and becoming inert if not used before you finish your next short or long rest.
Blood Hunter Level, Mutagens Created, Formulas Known
3rd: 1, 4
7th: 2, 5
11th: 2, 6
15th: 3, 7
18th: 3, 8
The number of mutagens you can concoct when you finish a rest, and the number of formulas you know, increases as you gain levels in the blood hunter class, as shown on the Mutagencraft table above. Additionally, when you learn a new mutagen formula, you can replace one formula you already know with a new mutagen formula. You choose four mutagen formulas to learn, and you can concoct one mutagen when you finish a short or long rest.
When you reach 7th level, your body begins to adapt to toxins and venoms, ignoring their corrupting effects. You gain immunity to poison damage and the poisoned condition.
Additionally, you can trigger a burst of adrenaline that lets you temporarily resist the negative effects of a mutagen. As a bonus action, you can ignore the negative side effect of one mutagen affecting you for 1 minute. Once you do so, you can’t do so again until you finish a long rest.
At 11th level, your mutagenic hemocraft lets your Brand of Castigation reveal a foe’s true nature. Any illusion or invisibility in effect on a creature when you brand it ends, and the creature can’t benefit from invisibility or illusion effects while branded by you. If a creature branded by you is in an alternative form (by way of the Polymorph spell, the Change Shape action or Shapechanger trait, the Wild Shape feature, and similar effects), it must succeed on a Wisdom saving throw or revert to its true form and be stunned until the end of your next turn. Whenever a branded creature attempts to alter its form, it must succeed on a Wisdom saving throw or have the attempt fail, and it is stunned until the end of your next turn.
Starting at 15th level, your blood curse can infuse a creature’s body with terrible toxins. You gain the Blood Curse of Corrosion for your Blood Maledict feature. This doesn’t count against your number of blood curses known.
At 18th level, your body has adapted to produce mutagens naturally in a moment of need. As a bonus action, choose one mutagen currently affecting you. Its effects and side effects end, and you can immediately have a mutagen you know the formula for take effect in its place.
You can use this feature a number of times equal to your Hemocraft modifier (minimum of once). You regain all expended uses when you finish a long rest.