Yogashikupanishad and chandogya Upanishad both have described 5 types of Agni
Anyone can translate it and give the interpretation of the five types of fire.
However the stupid materialistic people can only give an explanation based on the material types of Fire – like fire in wood , fire in atom, etc
But, for a yogi , a real yogi , the fires having nothing to do with material world
The upanishads, using very subtle puns, gave a divine interpretation To understand this full mastery over Sanskrit is needed. Right now there is NO ONE who can go into the very subtle aspects of Sanskrit who can lead people and give correct meaning
Bhavin