Burning is a physical phenomenon that emits light and heat, and these are the fundamental attributes of fire. The flame formed by my superpower is no exception.
Not only is the flame I summon composed of my spirit, but the light and heat emanating from it are also manifestations of my spirit. The application of thermal energy markers, and the past tactic of using light to invade Chen Long's "Teleportation Door Armor," are all based on this principle.
And because I concentrated all my mana into a compressed form, the resulting "Eclipse" naturally became a creation that does not emit light or heat. Despite still possessing temperatures high enough to destroy even time and space, it seems to be moving away from the definition of "flame."
This qualitative change reminds me of a discussion I once saw online.