Veiled dagger

You summon a thin veil of mist around your dagger, sharpening it increasing its damage with +2.

The mist wraps and whirls around the dagger, seeping into the wounds the enemy, dealing 1d4 cold damage on the next turn, If the target doesnt succed a CON saving throw (13+dex), when the mist returns to the dagger.

You can amass more mist and make it sharper as you level up (+2 damage increase at levels 5/11/17) (Increase die count with 1d6 at levels (5/11/17).