Blood Blade

You feel the tug an life of the blood around and inside you, begging to be freed. You oblige. You pull the blood from dead bodies around you and fashion it into a dagger that writhes with necrotic magic. If you choose, you can also create a dagger of your own blood by cutting yourself for 1d4 of damage. The dagger does 1d4+STR modifier, and also does 2d8 of necrotic damage as the foreign blood flows into a creature's body.