This upgrade of Inferno lets Amaterasu and Chibiterasu create fire on demand. With the seal of Moegami drawn, they can summon massive spheres of fire that has an enormous range (albeit mostly not visible). This sacred fire will deal heavy damage to most demons, especially those who are of the ice element. Fireburst can also be used as the Floral Finisher of demons whose finisher is Inferno, before the Solar FlareReflector is obtained.
To use Fireburst, draw the seal of Moegami on the Celestial Brush screen. The larger the symbol, the larger the flame and the more ink consumed (3,6 or 9 ink pots).
"Inferno's true power is unleashed when you draw the ∞ symbol. This is the power of Fireburst, a purifying flame that burns evil. Small symbols net little flame. Large ones result in more. It is possible to damage all enemies on the screen at once. The larger the symbol, the more ink is used. Depending on the size, it may consume 3, 6, or 9 Ink Bottles. Be sure that the ∞ is properly closed. Burn the grin off evil’s face with this powerful flame!"
"Okay, Chibi, I think you're ready to learn a new trick! This ain't your run-of-the-mill brush skill, so pay attention! If you draw the ∞ sign, you can create an everlasting inferno! These flames will set enemies and objects on fire! The bigger you draw it, the bigger the flames you get. Of course, a bigger fire uses up more ink pots. Draw the symbol with an unbroken line or else it won't work!"