The idea is simple, various monsters, represented as a class. Two that come to mind are the Vampire and the Werewolf. Obviously these would replace simply applying the template to a PC. From WotC, this is what I had for the vampire (warning, very skeletal):
1d8 hit die
armour proficiencies: None
Weapon proficiencies: Simple Weapons
Tools: None
Saving Throws: Wisdom, Charisma
Skills: Choose 3 from Acrobatics, Animal Handling, Bluff, Intimidation, Perception, Persuasion, Stealth, and Slight of Hand
Level Prof. Features
1 2 Unarmore Defense (Charisma), Blood Drink, Vampyric Sensitivity
2 2 Allure, Regeneration
3 2
4 2
5 3 Extra Attack
6 3
7 3
8 3
9 4
10 4
11 4 +Cha to attacks,
12 4
13 5
14 5
15 5
16 5
17 6
18 6
19 6
20 6 Die -> Misty Form thing
Blood Drink: When you hit an enemy with a melee attack, you can spend a Hit Die. Add the number rolled to the attacks damage, and gain that many Temporary Hit Points.
Vampyric Sensitivity: When in direct sunlight you have disadvantage on attack rolls and ability checks. You gain Resistance to Necrotic and Vulnerability to Radiant.
Allure:
Allure Save DC = 8 + your proficiency bonus + your Charisma modifier
You can have a humanoid creature you can see within 30 feet of you make a saving throw vs your Allure DC or become Charmed.
Regeneration: At the start of your turn, if your Hit Points are below half your maximum, you regain Hit Points equal to your Constitution modifier + your Proficiency bonus.
1d8 hit die
armour proficiencies: None
Weapon proficiencies: Simple Weapons
Tools: None
Saving Throws: Wisdom, Charisma
Skills: Choose 3 from Acrobatics, Animal Handling, Bluff, Intimidation, Perception, Persuasion, Stealth, and Slight of Hand
Level Prof. Features
1 2 Unarmore Defense (Charisma), Blood Drink, Vampyric Sensitivity
2 2 Allure, Regeneration
3 2
4 2
5 3 Extra Attack
6 3
7 3
8 3
9 4
10 4
11 4 +Cha to attacks,
12 4
13 5
14 5
15 5
16 5
17 6
18 6
19 6
20 6 Die -> Misty Form thing
Blood Drink: When you hit an enemy with a melee attack, you can spend a Hit Die. Add the number rolled to the attacks damage, and gain that many Temporary Hit Points.
Vampyric Sensitivity: When in direct sunlight you have disadvantage on attack rolls and ability checks. You gain Resistance to Necrotic and Vulnerability to Radiant.
Allure:
Allure Save DC = 8 + your proficiency bonus + your Charisma modifier
You can have a humanoid creature you can see within 30 feet of you make a saving throw vs your Allure DC or become Charmed.
Regeneration: At the start of your turn, if your Hit Points are below half your maximum, you regain Hit Points equal to your Constitution modifier + your Proficiency bonus.
