Adverbs for Merciless

coldly; vengefully; unsparingly; tyrannically; sternly; abominably; barbarously; brutally; savagely; uncommonly; cruelly; bitterly; terribly; ruthlessly; pitilessly; relentlessly; stonily; sanctimoniously; rigidly; unfeelingly; hard-heartedly; maliciously; basely; incredibly; immovably; unspeakably; habitually.