Who she is: Dagger, a.k.a. Tandy Bowen
Her power: Unknown for now, but the source material has her emitting a light force that she can form into daggers that can be fired. She also continuous builds up the light force, which must be periodically expended—usually into Cloak—to keep her healthy.
Her story: Unknown, but in the comics, she’s a wealthy young runaway teen from Ohio who ends up in New York City, where she befriends fellow runaway Tyrone Johnson (a.k.a. Cloak). The two are taken and experimented on against their will, developing the powers they then use to fight crime.
Played by: TBD
Currently, Dagger is: Waiting to come into existence.
Where will we see her next? Freeform is currently in development on the live-action Cloak And Dagger TV series.