5 minutes
As an action, you weave together threads of shadow to create a blade of solidified gloom in your free hand which lasts for the duration. You create the blade as a magical dagger, katar, sai, sickle, greatsword, kama, kukri, longsword, scimitar, or shortsword.
The spell ends if you dismiss it on your turn (no action required), if you cast it again, or if you end your turn without the blade in your hand.
At higher levels
When you reach 9th level, you can make an attack with the blade as part of the same action to create it.