Meet the Poison Starter Line, Toxtad!
Toxtad
The Toxic Tadpole Pokemon
Poison Type
The ponds they live in are inhospitable to anything but them. They secrete very potent toxins from their heads can take down a adult Human in three seconds. The only reason they're not a massive problem is because of their very underdeveloped legs
Ehnewt
The Virulent Actions Pokemon
Poison
Now that they have legs, they make themselves everyone's problem. They mark their territory by slamming their arms against rocks and trees. The thick gooey slime they leave behind kills any thing it touches.
Faelnder
The Apologetic Gaurdian Pokemon
Poison/Fairy
Upon evolution they see the wrongs and errors of their ways. They do everything in their power to atone for their past sins, healing and protecting the land from their poisons. Under the light of the moon, their healing ability is strengthened tenfold. Those healed by it are said to be blessed, and change the path of life they walk for the better.
Mega FaeInder
The Apologetic Gaurdian Pokemon
Poison/Fairy
Their penchant for chaos and battle has returned ten fold. They will rush into a fight, but not to harm. Instead, they will find those harmed and injured and mend their wounds. It prides itself on surviving a battle with a new scar, and lives saved.