They use nature and stealth to kill their victim 

Nature killer

You cannot fail at a nature based stealth check 

You also have advantage in survival

 

Nature spells

Use your nature magic to help you assassinate

Nature bonuses

Expertise in stealth and nature 

2d6 poison damage added to all slashing/ piercing damage 

Silent feet

Every time you roll under 12 in stealth or deception it becomes a 12

Nature’s greatest assassin

All damage you do has an extra 3d12 poison added

your stealth is now you’re INT+DEX+WIS

you get adv on all nature related things 

all animals have disadvantage attacking you