The first explosion occurred inside the dark mist. The extreme heat of the Steel Spear ignited the black particles that was the true form of the mist, incinerating them cleanly at a frightening speed into nothingness. After that, all substances within the mist were completely burnt off, and vacuum thus rapidly expanded, the great suction drawing in all matter in its surroundings to its center.
The second explosion occurred at the heart of the dark core. The Steel Spear hence pierced the dark core that almost arrived at boundary point, illuminating half the Void and the world of Kronos.
The dark mist's method of assault hence became the tool for Joshua and the others to retaliate against it.
Indeed, just a while ago, the other Legendary champions had launched counteroffensives of varying degrees, but was absolutely fearsome.
