Right just wanted to add this method because I know it worked for some other people, and it worked for me.
Mission 1, on hard in the airplane room. ill the 4/5 marionettes, and leave the fetish. Then stand a decent distance away from it, just out of range of its fire is good in my opinion. Then taunt it, and it should either do fire, throw its wheel things at you, war cry or JUMP! It took me maybe 5 minutes to get it to jump, and I dodged like an idiot, and maybe a couple more minutes to get him to do it again. Best method I have found so far. Health doesnt matter by the way!