Heartwarming / The Lives And Times of Kaleido Shirou Schweinorg

• Despite trolling Shirou to kingdom come, OS obviously still cares a lot for Shirou, and doesn't want (permanent) harm to him.
  “Just wanted to let you know,” Continued the weapon, its tone solemn. “If you just killed my partner, I will make sure neither of us leaves this ‘verse alive.” OS spoke with a quiet conviction, having stated nothing but a simple and absolute truth.