Adverbs for Unmerciful

strangely; significantly; remarkably; unwontedly; unaccountably; oddly; cruelly; coldly; miserably; hatefully; inflexibly; stubbornly; boorishly; brutally; selfishly; unyieldingly; dreadfully; intractably; shamefully; scandalously; wickedly; immovably; sternly; inscrutably; mysteriously; surprisingly.