Vampires

Vampires in Mythos 3 are infertile, have health boosts, additional personal combat skill, a hunger meter, and the hidden vampire trait.

Reproduction
In order to keep the dynasty going, vampires must offer their "gift" to willing individuals, or those imprisoned in their dungeon, and then select the "welcome into the family" option to add the character to your dynasty if they accept. Characters with bad personality traits, such as Envious, or Cruel are more likely to accept, as are your direct vassals and characters who have a high opinion of you. Anyone you personally turn gets the Obedient opinion modifier and will do just about anything you ask of them.

Feeding
Every month a vampire's hunger will grow, giving them additional combat skill and intrigue, but if they get too hungry, it is very likely an event will proc where they attack a courtier and are revealed to be a vampire. When feeding there is also a chance the vampire will be caught. They are more likely to be caught if they take a lot of blood and kill the victim, but they also have the option to only take some blood and reduce their hunger a little. Feeding can heal a vampire's wounds, but vampires need to be careful because if they feed from a person who has a disease, they will get the Tainted Blood modifier severely reducing their health and sickening them. Be careful about having a lot of vampires in your court as it's very easy to run out of human courtiers very quickly.

Being Discovered
If a vampire is discovered they will suffer a massive opinion penalty due to people not liking vampires, this will make it hard to near impossible to invite characters into your court and cause your vassals to become unruly. Additionally the known vampire trait applied to your character visibly reduces fertility to the point where arranging a marriage becomes impossible with anyone who has the option to refuse.

Vampiric Culture
A revealed, independent vampire ruler of at least King rank will have the option to establish Vampiric culture which will offset the opinion penalty of being a known vampire with anyone who has vampiric culture. They can attempt to establish a vampiric empire but will likely be beset by enemies on all sides.

Luciferian
Vampires can convert to Luciferian at any time, and vampiric relatives of yours who have been revealed may convert on their own whether you want them to or not. Luciferian is functionally very similar to Catholicism, but has been made specifically for Vampiric characters similar to vampiric culture.