Base Class: Druid
Druids of the Circle of the Monster are ferocious and aggressive. They are relentless fighters that have affinity with their monster counterparts. Rejecting the usual druid way of protecting, they usually live in isolation within dark caves and are very territorial over their space.
With their monstrous nature, they can transform into dark beings such as a Cockatrice or Darkmantle. Even becoming powerful enough to harness their magic to transform into a Lamia. They also harness this to cause fear in those who have the misfortune of running into them.
Monstrous Wild Shape
While you are transformed by Wild Shape, you can use Bite or Claw as a bonus action instead of an action, as many monsters have these abilities.
Circle Forms
Monsters are powerful creatures, therefore you can only transform into certain ones. At level 2, you can transform into a monster up to 1/2 CR. At level 6, it becomes 1 CR. At level 10, 2 CR.
Teraphobia
At level 3, whilst in your Wild Shape form, you release a terrifying aura as you transform into a creature unlike any other. Creatures in a 30ft radius from you must make a Wisdom saving throw or be frightened.
Alpha Monster
At level 6, you gain the ability to use an action to Turn Monster. Similar to the Turn Undead ability, any creature marked as a monstrosity within 30ft of you must make a Wisdom saving throw or be "turned" for a minute or until they take damage.
Monstrous Vigor
As a monster, your savage nature makes you harder to take down. At level 10, you can expend a reaction to remain in your Wild Shape at 1 HP, where normally you would transform back into your original self. You may only do this once a day.
True Monstrosity
You have unlocked your monstrous capabilities and at level 14, you gain the ability to transform into a Lamia (CR 4). However, you can only do this once per day.
You may also give advantage to attack rolls against enemy monsters to anyone (including yourself) in a 10ft radius. You can only do this once per long rest.