DFang: lol

Johnson would rip out Forge's spine and choke him with it.  I mean, he did it to a brute, so he can do it to a human.  

 I seem to remember SgtMaj Johnson got manhandled by a Brute as if he were a baby two times. Hell the Chief and the Arbiter (Thel) are wary of closing with them. Unless Thel has his sword, then he's game.

Seriously I think it be a tough fight as they are both marines, but I think Johnson would be able to beat him. Also Johnson's S1 status is dubious at best.

Also Kymon, what happened at the end of Halo1 on legendary was a joke, not actual canon.