Complex sentence: Upon entering one of the rift gates, the warriors encounter a dark sphere in which Sophia explains it is a substance found only in the rift known as Dark Matter and that Avalon's goal is to harvest it for their evil purposes.
Split into simpler sentences: Upon entering one of the rift gates, the warriors encounter a dark sphere. When shown to Sophia, she explains it is a substance found only in the rift known as Dark Matter and that Avalon's goal is to harvest it for their evil purposes.