According to a recent comment, someone wants help with Captain Hunt. Stun the sniper when it's about to use it's big attack. You could use crystalize to give yourself time to regen . .That's pretty much all you need. I didn't find the battle hard enough to need a particular strategy (like the Baron, who you need to kill the focus of.) By the way, if you're a psycho, respec after the Baron because haunt is pretty much useless after that.
Hard time beating the baron? Hydraulics suck for this, but for bios, max out disrupt, and you destroy all his focus instantly. Then he has to hurt himself to get it back. Psychos, get haunt and traumatize to destroy his focus. If you have a problem with tick tock, psychos can use salvation to make Veradux heal better and free will as well. Bios can use reform, but I didn't find it necessary to use.
The legend achievement should be easier to get and the difference between challenging and heroic should be harder enemies, not timed attacks. At times, there are so many buffs on you and your enemy that you have to mouse over them and see what they are to make the best move.