The function of "demo" in the following sentence: 遥か彼方で炎でも燃え盛っているように、紅蓮の光は形を変え、踊る。 [duplicate]

Question

So in the sentence below what would be the grammar function of 炎でも?

遥か彼方で炎でも燃え盛っているように、紅蓮の光は形を変え、踊る。

I can understand the overall meaning, but I am struggling with how to phrase this part.