Kira yelped as Lucifer's teeth unexpectedly made contact with the soft flesh of her hip. That action alone summed up her hatred for her brother and clearly proved her assumptions wrong that their deal would get him off her back. He didn't need to make her life miserable, he did that by being his violent self everyday and haunting her dreams at night. She found it best to not answer nor make any form of a gesture that Lucifer might interpret as a disrespectful act of insubordination to his precious deal, she understood alright and now had a pain in her leg as a temporary reminder. Understanding, she just bowed her head to him and limped following Stormy's footprints.
That one day where maybe Lucifer would hold up his end of the bargain washed heavily over Kira, it would take an eternity to arrive if it ever came at all or if death happened to intervene first.