The entire world was filled with red flames, scalding magma, and an active sea of fire.
At a great distance, this would feel like a sauna, but at a close distance, it would be no different from being baked in flames, and if you tried to walk through here, you would burn to death unless you had fire-resistant equipment and potions.
The sea of fire wasn't quiet at all. Various strange creatures of fire were crawling out from within. They furiously attacked everything before them, including their own kind. And when their short lives reached the end, violent explosions and a return to the sea of fire would signify the end of their lives.
Fire element creatures were everywhere. Fire lizards, low-level fire elementals, magma monsters, flame wolves, and so on were all cruelly killing each other. The victor would be able to devour the loser's elemental core for swift growth.