Possible Clues:

• Opposite of cheer
• "... nor ___ of night..."
• Doom's accompaniment?
• Good to take on threatening shape in darkness
• Dark disheartened girl, low, retiring
• Bottom of cooling tower is dark
• Initially glimpsed weaving machine in partial darkness
• Pessimistic outlook
• Partner of doom
• What a rain cloud over a head may represent, in comics