Mandi Schwartz, a Yale hockey player known for her tenacity on the ice and during a nearly two-year battle with cancer, died Sunday at the age of 23.

Schwartz, who died in Regina, Sasketchewan, had acute myeloid leukemia and was the subject of a coast-to-coast bone-marrow search (her heritage made her a difficult match) that ended just as her brother, Jaden, was being drafted by the St. Louis Blues in the first round of the NHL draft last June.

“She means the world to me,” Schwartz said after being drafted. “She is the best sister I could ask for. She's been a role model for me growing up. We've been close her whole life. It's not easy not having her here. But I know she's proud and she's watching right now.”

Although she underwent a stem-cell transplant, her cancer returned just after Christmas and treatment was stopped in January. Jaden, who has able to spend time with his sister as he recovered from a broken ankle, and his brother Ryan both play for Colorado College and have spent as much time together and with their parents and sister as possible.

“Any time you have a family member right there with you, it helps,” Jaden said 10 days ago at an NCAA hockey regional. “It’s been tough over the last couple years with Mandi battling. Whenever we need to go somewhere, we go together. When we need to talk, we talk. It’s been a big help having [Ryan] here. I know my parents like having the two of us together.”