Roaring Flame Sphere

After the fourth war, Naruto Uzumaki became a legendary figure in the shinobi world. With this repute in the heroic Kage, the same emphasis was placed in his abilities. The abundance of the Rasengan's usage in Konohagakure shinobi flourished. Anywhere Reikon looked, some genin wished to learn the Rasengan. Observing its usage and appearance, he formed his own unique attack named the Roaring Flame Sphere (哮炎丸, Kōengan) which incorporates the parent jutsu with condensed flames for tremendous results.

Usage
There are three steps required to form the technique:

Shape Manipulation :  The user must first transform the chakra into a sphere, adhering the fundemental principles of the Rasengan. Once this is formed, the user shapes the chakra into a sphere, slightly of lesser power than the Rasengan, but with the same size.

Nature Manipulation :  The second step of the technique is altering the form of the sphere to fire. Instead of merely breathing fire into it to ignite it, the chakra itself is altered to completely transform into a sphere of intensely hot flames.

Density Manipulation :  Perhaps the most critical part of the technique, the user imbues more chakra into the sphere whilst still mantaining its size, increasing the density of the fire in the sphere. The results of this density are temperature multiplied tenfold, easily disintegrating anything it comes into contact with, and then a powerful explosion in a frontal form after being thrust, decimating opponents and reducing them to ashes.