Elements had distinct features that made them different from each other. Those qualities didn't identify them since spells had various effects, but their nature was to follow them.
Light and darkness were complete opposites, and they even repelled each other.
The light element was soft, almost weightless. It could fill entire areas without affecting anything, and it focused on purity rather than sheer quantity.
It was calm and captivating. Some of Daniel's leadership skills came from his innate aura as a cultivator with a light aptitude.
Instead, the darkness element was heavy. It was violent and abrupt, and it didn't care about anything that it destroyed in its expansion.
Darkness appeared able to engulf everything. It strived for quantity, and it didn't stop at anything.
Both elements shared similar features too. They were a core part of the world's fabric, and they were everywhere. They also tend to expand as long as they had space.