User can create and manipulate venom

Pros:
-user can control effects of venom
-user can control speed of venom in the body
-user can create any venom they want
-user is not effected by their venom
-user can create helpful venoms
-user can create antidotes

Cons:
-user can't control random effects that will appear
-user can't control how the poison is take into the body
-user will always have random elements
-user is severely weak to natural venom
-user can't make many useful venom with no side effects
-user must have the venom in their body to create an antidote

Weakness: natural venom
User is easily killed as their immune system is so weak