>>43797306AKSHUALLY
The creation of the chaos flame wasn't the reason Izalith was destroyed. Demon society actually flourished for a time as evidenced by the architecture and statues made in the image of demonkind and the fact that a Daughter of Chaos guarding the Bed of Chaos fog door remains a human, implying that transformation into a demon was voluntary. The destruction of Izalith and the decline of demonkind can more likely be attributed to Gwyn and his war against them which led to the creation of the Black Knights. This fits more with the theme of Dark Souls as it is once again Gwyn's aversion to new and rising powers that he sees as perversions of his perfection that ultimately leads to the downfall of his entire civilization.