I am wondering if I got there too soon. It took me a couple of tries with Doshia, but even failing it was obvious I was doing enough damage and if I could just take a little less while doing it I could win. I have also faced off with a number of other bosses (mini bosses?) in quests and either beat them the first time or had the similar experience of taking a couple of tries but seeing that winning was within reach when I died. But Gutsripper has killed me several times and I have barely done any damage.
I am playing as a High Elf Templar, lv 10. My main weapon is a lv 9 Prophet's Greatsword. When starting the fight, I hit Gutsripper with a couple of Javelin I throws, a Radial Sweep (Ultimate Ability), Puncturing Sweep and Sun Fire Morphed to Vampire's Bane I. That's game over for a lot of mini bosses before I even take a swing at them with the sword. The damage from all this barely registers on Gutsripper's health bar. Then when I start swinging the sword, i take massive damage and am pretty quickly running for my life. I have done a meal before and burned through all of my health potion without doing more than maybe 20% damage to Gutsripper before I died.
Do I need to go back at a higher level or is there some special strategy that I need to be using?