I lost to these guys so many times that I planned to ignore them, rewards were not worth it. I was hex at that time and even with a havels I kept dying in one mess up -gets claw swiped and before I could roll I've spikes kill me wtf- I farmed loyce souls and went back to being tank. After I killed him I went back and I won on first try. Havels, santieres spear to poke. Try to stay under luds belly the whole time and when not in then align them so only have to worry about one when one casts ice run under one. Try to focus on lud because he doesn't get buffed when nearly dead. When zallen close he gets enraged and heals faster than you can hurt so lud first. Stay under zallen when enraged. Biggest tip is tank the claws instead of dodge. Havels+40 end and they can't claw through anything. (Take the npcs, they good distractions when you need to heal