Just wait until he uses holy scars and hit him with your most powerful attack! no matter what the risk put everyone on relentless mode so they can use their most powerful attack!
lol @ daleksparta, this is a Sonny 2 forum, not a Sonny 1 forum, so maybe if you go play Sonny 2, you might know what we're talking about, and it is very challenging since Baron does that Tick Tock (I think)
The baron is a b*tch to kill on heroic as a hot hydro (ended up respeccing completely to a cold hydro simply because hot hydro has no defensive skills).
Anyways, on easy mode, its rediculously easy if your a bio, get two points in disrupt, use disrupt on him, hope that he uses dark burning before shock therapy heals back too much focus (he usualy will use dark burning pretty soon). If your a psycho, use haunt and traumatize, which is slower than disrupt (5 focus per turn for haunt and 15 for traumatize), but still better than if your a hydro. For hydro your only focus removing skill is regulate, and it only remmoves 10 focus (only 5 on level 1). It's slow as heck, but in easy mode you should be able to put up with the slowness of regulate anyways.
Uh.... You really should have stayed a cold hydro, you would've still had some chance. You might be alone on this one. But you should max out regulate. Use it on him, cast a defensive ability, then when he's hurting himself you should use a weakening ability so he takes even more damage.