The Slayer has a history dating back further than anyone really knows but the accepted understanding of her is that a group of male wizards imbued great power within a girl and cursed her to protect our world. Only females can be chosen to continue the Slayer line meaning only female characters will be able to select vampire slayer as their class option.

Slayers are women who carry a huge burden on their shoulders, they have been chosen to protect the world from evil. How does your character feel about that? Does she resent other characters for their care-free attitude or does she relish the responsibility? How did your character find out she was a Slayer? Was she ambushed by a evil creature and her instincts kicked in? Did she not fully understand her power and do something she now regrets? Has she had to try and come to terms with her powers alone or was she guided by a mentor? Where is this mentor now?

Prophetic Dreams

Starting at 2nd level when you choose this school, glimpses of the future begin to press in on your awareness. When you finish a long rest, roll two d20s and record the numbers rolled. You can replace any attack roll, saving throw, or ability check made by you or a creature that you can see with one of these foretelling rolls. You must choose to do so before the roll, and you can replace a roll in this way only once per turn.

Each foretelling roll can be used only once. When you finish a long rest, you lose any unused foretelling rolls.

Slayer's Sense

Starting at 6th level, . Until the end of your next turn, you can sense the presence and location of any fey, fiends, undead or celestials within 60 feet of you that are not behind total cover. You also know their numbers, but you can only discern their identity with this trait if they are a vampire. You can also sense the presence of any consecrated or desecrated areas within that same radius. You can use this action a number of times a day equal to 1 + Your Wisdom Modifier. You cannot be surprised while this is active. Also, you can spend 2 Ki points when you use it to increase the duration to 1 minute. At 11th level, the cost to extend the duration becomes 1 Ki point.

Divine Restoration

Starting at 6th level, you regain 1 Ki point when you reduce a hostile creature to 0 hit points. You must finish a long rest before you will gain this ability again.

Vampiric Aspect

At 11th level, you have learned to channel your Ki to emulate the powers of a vampire. You can cast Charm Person (2 Ki), Invisibility (3 Ki) and Vampiric Touch (4 Ki). Additionally, you can spend 3 Ki to give yourself advantage on any Strength or Dexterity ability check or saving throw. Your spellcasting ability modifier is Wisdom.

Slayer's Resilience

Starting at 17th level, you have achieved incredible skill. You use your Ki flow to regenerate from wounds rapidly. At the start of each of your turns, you regain 5 + Your Constitution Modifier HP. Only functions if you have more than 0 hp and less than half of your hit point maximum.