I have several sentences for you.
It's used as a noun. Another example without personification:
I stepped into the darkness of the cave and couldn't see anything.
"The day was sunny and did not match our dark, dark souls."
Example sentence - The fur on the bear is dark brown.
"As i went outside to take out the trash, everything was dark."
the cat was spritely in the dark
The detective was sent to investigate the dark room.
The boy was curious about what was in the dark room.
the woods was filled with silence and darkness.
A sentence using countless:Isn't it amazing how the countless stars scatter the dark sky?
He wanted to read but it was too dark.
She was the yin to his yang, the dark to his light, the perfect balance to him.
She descended down the dark staircase.
i selfishly took and ate her dark chocolate.