Chisato Nishikigi

Age: 17 (Episode 1-7); 18 (Episode 8-13)
Birthday: September 23
Blood Type: AB

Said to be the strongest Lycoris of all time. She enjoys solving private-sector problems that the DA would not address. At Café LycoReco, she works joyfully and cheerfully as the self-proclaimed poster girl.

It is later revealed that she is one of the "Alan Children", which are essentially prodigies. With a mechanical heart that was provided by the Alan Institute. Specifically by Yoshimatsu Shinji.

Her mechanical heart was later destroyed by Himegama, leaving her 2 months to live out. Although the heart would fail by the time she hit adulthood anyway. At the very end, she received a new version of the heart, that should keep her alive.
(Source: Official Website)