These arrows are extremely dangerous. You Must make a DC 15 Constition modifier per arrow or take 2d4 poison damage on a failed save or half as much on a successful one. Targets you hit with these arrows must also make that saving throw or take 2d4 poison damage on a failed save or half as much on a successful one. Additionally these arrows do 3d6 necrotic damage despite your dexterity modifier or with what weapon they are fired from. The distance these arrows fire is determined by the weapon. Additionall once these arrows hit something they shatter on impact making them unrecoverable. 

Notes: Damage: Necrotic, Damage: Poison, Damage