A true giant in a fiery texture. The opponent may seem invincible, but there is a simple way to defeat him.
There is one very simple tactics, where in fact we do not fight demon, but apply a trick instead. It is about luring him to the fogy passage next to the starting point on the arena. Wait until he hits the ground with his limb and then hit him quickly several times In this way demon will lose anchor point (his limb) and fall into abyss.
If you do not want to act this way (but why not ?!), you can kill him with a bow, hiding behind rocks. But you might need a really good bow and many arrows.
You can also defeat enemy in a melee fight. You have to equip weapon and armor capable to resist his fiery blasts and attack him in between.