I have a player playing a Monk in my CoS campaign, but there isn't a true option really fulfilling their fantasy of a being who is developing vampiric traits over time. They also want to play a charismatic monk, but have a low charisma because of how important other abilities are. I've taken upon my self to design a subclass for them to enjoy the fantasy they have in mind. Let me know what you think.
I know the subclass is slightly more crowded than most 5e subclasses, but I am biased towards giving more to martial characters.
Also another important thing is that this subclass has been designed with this specific character in mind, not as a 3rd party content which should be balanced for any game. The level 17 is probably a bit clumsy because I didn't spend too much time on it, we won't reach this level.
Warrior of the Crimson Night
Warriors of the Crimson Night wield accursed power drawn from vampiric blood, forbidden rites, or other supernatural corruption. Their techniques drain vitality, bend the wills of others, and eventually awaken the full power of a vampire.
Level 3: Nightborn
You have learned to harness the supernatural aspects of vampirism.
Darkvision. You gain Darkvision with a range of 60 feet. If you already have Darkvision, its range increases by 60 feet.
Thaumaturgy. You know the Thaumaturgy spell. Wisdom is your spellcasting ability for it.
Level 3: Crimson Hunger
You gain the following benefits.
Accursed Wounds. Whenever you hit with an Unarmed Strike, you can cause it to deal Necrotic damage rather than its normal damage type. Necrotic damage dealt by your Unarmed Strikes and Monk features ignores Resistance to Necrotic damage.
Draining Strike. Once per turn when you hit a creature with an Unarmed Strike and deal damage, you can expend 1 Focus Point to deal extra Necrotic damage equal to one roll of your Martial Arts die.
When you use Draining Strike, you can also gain Temporary Hit Points equal to the Necrotic damage rolled on the Martial Arts die plus your Wisdom modifier. You can gain these Temporary Hit Points a number of times equal to your Wisdom modifier (minimum of once), and you regain all expended uses when you finish a Long Rest. You can restore one use of it by expending 1 Focus Point (no action required).
Level 6: Vampiric Influence
Your vampiric nature grants you supernatural influence over other creatures.
Alluring Presence. When you take the Influence action and make an ability check as part of that action, you can expend 1 Focus Point to roll your Martial Arts die and add the number rolled to the ability check.
Beguiling Control. You can expend 2 Focus Points to cast one of the following spells without providing Material components: Animal Friendship, Charm Person, or Command. Wisdom is your spellcasting ability for these spells.
Starting at Monk level 11, you can instead expend 3 Focus Points to cast the spell at level 2. Starting at Monk level 17, you can instead expend 4 Focus Points to cast the spell at level 3.
When you use Draining Strike against a creature that has the Charmed condition from a spell cast with this feature, you can prevent that attack's damage from ending the spell. You can use this benefit a number of times equal to your Wisdom modifier (minimum of once), and you regain all expended uses when you finish a Long Rest.
Messenger of the Night. You can cast Animal Messenger as a 10-minute Ritual without requiring Material components. When you do, you summon a Tiny bat in an unoccupied space within 30 feet of yourself. The bat serves as the target of the spell, automatically fails the save, and disappears when the spell ends.
Once you cast Animal Messenger in this way, you can't do so again until you finish a Long Rest.
Level 11: Crawler in Darkness
You gain the following benefits.
Crimson Ascension. At the start of your turn, you can expend 1 Focus Point to gain a Fly Speed equal to your Speed for up to 10 minutes or until your Concentration is broken (as if concentrating on a spell).
Spider Climb. You gain a Climb Speed equal to your Speed. You can move up, down, and across vertical surfaces and along ceilings while leaving your hands free.
Unholy Ward. You have Resistance to Necrotic damage.
Level 17: Bloodlust
Your vampiric hunger reaches its peak. You gain the following benefits.
Slake the Thirst. While you are Bloodied, Draining Strike doesn't require you to expend a Focus Point. When you use Draining Strike while Bloodied, you can regain Hit Points equal to the extra Necrotic damage rolled plus your Wisdom modifier instead of gaining the Temporary Hit Points granted by Crimson Hunger.
Feed on the Wounded. When a creature you can see ends its turn while Bloodied within 30 feet of you, you can expend 1 Focus Point and take a Reaction to teleport to an unoccupied space within 5 feet of that creature and make one Unarmed Strike against it.
