The mana materialized as fire that was hidden within the Heavenly Apocalyptic Blaze was actually the Vairocana Pristine Cleansing Fire formed from Buddhist sources of power. This was a Buddhist flame that was pure and without a single trace of blemish and its flames were completely transparent. Even though it was not listed amongst the Seven Legendary Primordial Fires, its essence was possibly superior to the Acalanatha Inferno.
Typically, the toughest challenge to one who wished to assimilate and control the Heavenly Apocalyptic Blaze was the fact that the process required personal mana exertion. However, if you used personal mana to assimilate the flames they were all bound to be consumed by the Heavenly Apocalyptic Blaze.