Prerequisites: Poisoner’s kit proficiency
As an action, you expend Maneuver Dice (up to your Proficiency Bonus) and use your poisoner’s kit to craft one vial of Greater Poison.
It retains potency until the end of your next long rest. You can’t regain your Maneuver Dice until this Poison is spent.
With the Use an Object action, a creature can apply the vial of poison to a weapon or piece of ammunition. On its next hit, it deals bonus poison damage equal to the Maneuver Dice spent, and the target must succeed on a Constitution saving throw or for 1 minute it has disadvantage on attack rolls and ability checks, its speed is halved, and it can’t take reactions.
The affected creature can repeat this saving throw at the end of each of its turns. On a success, the effect ends, but on a failure, it takes poison damage equal to your Maneuver Die.