2. Anna Turner and Kelly Severide
Kelly Severide has had a bizarre romantic history. Stella Kidd has been the one for him, but there were stretches of Chicago Fire where it seemed as though he might decide to settle down with someone else. Anna Turner (Charlotte Sullivan) was one such example.
Severide and Turner met after the former dedicated bone marrow to the latter. They entered into a brief relationship, but things took a turn for the tragic after Turner's leukemia returned worse than ever, and ultimately claimed her life.
Severide hasn't really talked about Turner's death in recent years, but it was obvious at the time that it left an enormous impact on him. It's worth remembering.