1) Blackly 1) In a sinister fashion 2) In an ominous way 3) In darkness 4) Mysteriously 5) Not lightly 6) With pessimism 7) Without light 
• (adv.) With imperfect light, clearness, or knowledge; obscurely; dimly; blindly; uncertainly. • (adv.) With a dark, gloomy, cruel, or menacing look.
Dark'ly adverb 1. With imperfect light, clearness, or knowledge; obscurely; dimly; blindly; uncertainly. « What fame to future times conveys but darkly down.» Dryden. « so softly dark and darkly pure.» Byron. 2. With a dark, gl...
[adv] - in a dark glowering menacing manner 2. [adv] - without light
in darkness adverb without light; `the river was sliding darkly under the mist`