The Dark Card
The dark card is the other half, the half that makes up the dark part of
everything and must appear with the light. Dark appears in episode 42 and
blanketed everything in darkness during Sakura's school play. Light emerged
from Sakura and they combined and were reunited. Dark and Light were sealed
together and they told Sakura who her tester was going to be. (Not that
it mattered much because she didn't really know who it was anyway.
When Dark is summoned from her clow card form, she has the ability to
spread her powers of darkness and ingulf everything. She also has the divine
power to change day, into night.
