Plague master

The plague master is a vermin kin that has devoted its studies to harnessing pestilence and plague

the plague master has proficiency with alchemists tools and chooses one of the following skills to be proficient in:
medicine
slight of hand
Acrobatics
stealth

Potent poisons
once per turn when the plague-master deals poison damage they can add their proficiency bonus to the damage as poison damage. also whenever the poison master forces a target to make a save that would inflict poisoned the target must make that save with disadvantage

Power Vermin

The Power Vermin is a Vermin-kin who was infused and warped their body with potent chemicals and infusions being able to turn their bodies into hulking machines of muscle they are some of the most feared Vermin-kin warriors. 

The power vermin has proficiency with alchemists tools and chooses one of the following skills to be proficient in:  
Athletics  
Intimidation  
Acrobatics  
medicine  
  
Enhancing concoction
At level 1, you can cast Thaumaturgy at will.

At level 3,
Using a bonus action, the power vermin can inject itself with a strange chemical concoction to infuse your body with strange chemicals and magic for 1 minute.

You can use this ability to have +2 AC on yourself as the concoction hardens your skin.

At level 5,
Using a bonus action, the power vermin can inject itself with a special concoction that makes it grow or shrink vastly in size

You can use this ability to cast the Enlarge/Reduce spell on yourself without concentration as the formula vastly increases or decreases your body size.

You can use each of level 3 and 5 abilities once per long rest you cannot benefit from both both abilities at the same time.