Almost immediately after loading up the Dark Souls: Nightfall demo, you will navigate through the Demon Ruins and find yourself in the Demon Firesage’s boss room. Oddly empty, you will notice a Wellspring on the far end, and just as it looks like you’re about to clear the room, the Blistering Demon will block your path. Here’s how to beat the Blistering Demon in Dark Souls: Nightfall.
First, if you haven’t already, activate Sprite mode by pressing Y (triangle on a Playstation controller and X on a Switch Pro). The Blistering Demon, and almost all of the encounters from this point on, are actually harder when using normal Dark Souls mechanics. Blistering Demon attacks very fast with very little recovery period, so you need to learn how to attack and dash away — similar to Bloodborne or Sekiro’s combat.
Most of his attacks are dodgable by dashing to his right, however, if Blistering Demon raises his weapon to spear it into the ground, you should backdash away. The hitbox on that attack is very unforgiving, and will auto-correct to target you even if you dash behind him. At approximately 75% health, he will ignite, gaining a few new attacks.
If Blistering Demon raises his weapon and summons a glowing light, backdash as far away as possible — he’s about to fire off a massive magical AoE attack that will take away 80% of your life. If he starts to spew fireballs, you should dash in and get a few free hits, as he’s locked into that animation for several seconds. Once he gets down to 30% life he will ignite further, gaining faster attack speed and a five hit combo that should simply be avoided entirely — the tell for this is a mighty roar.
If you take a hit and want to heal, you can trap the Blistering Demon on the large roots on either side of the arena. Only the largest roots are unbreakable, however, so make sure he’s trapped in a running animation before turning off Sprite mode to heal. Follow these tips and time your dashes well, and you should have the Blistering Demon down in no time.