Light and Darkness

Light, what we see in the start.
Darkness, what we see during and at the end.
Way bright, we see during the day.
In the black as we see at night and at death.
Light, the source of life.
Darkness, the source of nightmares and death.
They both need each other,
Or the other dies or dominates.
Without darkness and death we could be cold and overpopulated.
Without the Light the earth would be barren.
They blame each other like Yen and Yang.
Yet they are constantly at war with each other.
Bickering like siblings in the same room.
And civilized as generals in the same field.
They share the earth as night and day.
And they chase each other everyday.
The Sun and warmth.
The Moon and cold.