Tip if you're using a Magneto(any star) for Darkhawk.
Maybe this post is a bit late, but I saw lots of people saying it took them couple of revives. I have a feeling that most people throw the sp3 as soon as they get to 40, don't do this. 40 prowess will be killing with a r5/r2/r3, but if you're using anything lower: Remember that his heavy prowess stacks to 99. So even after you get to an sp3, throw as many heavies as you can while you're alive, then charge to get the 30 expiring prowess, then throw the sp3.