There's quite a lot of bullshit going around in this story, but the explanation about synthesizing the white-moss actually made me pause.
The heart is needed, because it "emits heat"? What? Does that mean any warm-blooded creatures are "Yang" attributed, because they produce heat?
Just be straightforward with the fantasy-bullshit, and say "These creatures evolved fire-attribute to contrast the water-attribute of the moss."
I expect Chinese stories to be needlessly round-about and pointlessly verbose with their descriptions, but not Korean ones.
And if I am already ranting, I also want to add that "My brother is apparently a walking wikipedia and knows everything that is immediately useful, how convenient" has already gotten old...Oopth.