Hatsuna is a magician who escaped the laboratory. She has the ability to resurrect herself so cannot be killed by any physical harm. However, she will still die if she stops consuming pills.
She was the last magician who escaped during the transportation incident, and found enough pills in the transportation vehicle so she can survive for so long. However she was tracked down by Valkyria and almost all her pills were taken away, it left her no choice but to join Murakami and his company.
It is confirmed later that she also has the ability to heal others, at the cost of her body to melt (which won't kill her unless she hanged up). Up till now, she already used this ability to save Murakami and Kazumi once.