darker

Having an absolute or (more often) relative lack of light.

“The room was too dark for reading.”

(of colour) Dull or deeper in hue; not bright or light.

“my sister's hair is darker than mine;  her skin grew dark with a suntan”

Hidden, secret, obscure.

Without moral or spiritual light; sinister, malign.

“a dark villain;  a dark deed”

Conducive to hopelessness; depressing or bleak.

“the Great Depression was a dark time;  the film was a dark psychological thriller”

Lacking progress in science or the arts; said of a time period.

With emphasis placed on the unpleasant aspects of life; said of a work of fiction, a work of nonfiction presented in narrative form or a portion of either.

“The ending of this book is rather dark.”