Hunter || Natasha Romanoff

Daniel Smith a.k.a Hunter, at the age of six, along with his sister was abucted by an Organization called S.A.T.O.R. , who had came into the possesion of The Tesseract. Daniel was experimented on and he then became one of the most ruthless assassins in the world. What happens when he decides to make a deal with S.H.E.I.L.D. to destroy the league and works alongside a certain redhead.
Disclaimer: I do not own any characters apart from my own OC's. All rights go to Marvel.
Pre-iron man - Avengers endgame and further if possible.