The world of ice and snow continued to expand as nothing but white could be seen extending into the horizon. The entire world around us was now pure white.
Based on the typical rules, when two Soul Worlds clashed, the end result would depend on the Soul Worlds' power and the strength of their users. If there was little difference, then both sides would have equal chances to win. If one side was far stronger than the other, then the weaker person's Soul World wouldn't be able to do anything other than protect them.
As for us… there was basically no difference, at least on the surface.
What would white be when it was combined with white? Looking around us at this world filled with ice and snow, Zero was surprised that the two master ice mages' Soul Worlds didn't actually clash. They melded perfectly together. This obviously went against the common sense of Soul Worlds, which made her both astonished as well as faintly realize that something was wrong.