You beat the beast solo! Congratz on that! I'm still trying myself. In my longest run the thing just wouldn't die. It's frustrating but I'll get it eventually.
since they don't have a health bar, so its hard to tell if you are having a skill issue or a gear issue, i changed all my gear multiple times(and it took much longer than the fight itself), when i was using ice weapon it seemed easier to stop the first explosions, but i also felt lazy on the dps and didn't seem to have enough for the kill. when i changed to dragon i had to try harder early, and looks like it paid off!(so it was a skill problem) anyway gl on your runs!