Is Recommended to use Protection Amulet to reduce physical damages. Druid or Sorcerer: Use Magic Shield and shoot SD as fast as you can if your level is lower than 50. If your level is 45 or lower use 1 to 4 SSA to make mana last longer since almost all the damage you take is melee.
At level 70 or higher you can use Ice Strike and Exura. Knight: Use melee and Exori and Strong Health Potions. Make sure your health is always high because this boss can take even experienced knights down with big comboes. Paladin: Use Shield, Ethereal Spear and maybe even Icicle to kill him fast.