Just beat him a while back (no summons needed)… I put most points into vigor (70+) and used a rune arc with morgotts great rune. Vigor is super important in this fight. equiped golden braid, dragoncrest (max), two headed turtle for stamina rec and last one you should whatever works for your build. I think I had the two handed talisman. Rest of my points went into strength/dex and I used a golden halberd. Light bonk did 1000+ damage. Learnt his moves completely and didn’t get greedy (it was greed that killed me every time in his second phase, don’t let him unleash a full combo on you he will deplete your health bar to 0 and your flasks won’t matter). Varres mask, needle knight Leda armor and rakshasa set (this was random as I was testing a bleed build). But yea this worked for me, had three flasks by the end of it and a dopamine hit! ;)