Darski was rushed to the hospital on 8 August 2010 for unknown reasons. All upcoming Behemoth live shows were cancelled. On 24 August 2010, Darski was diagnosed with leukemia. The illness was thought to have advanced far enough to make chemotherapy useless, but these reports have since been proven false. His then-fiancée offered to donate her marrow, but his marrow didn't match. On 8 November 2010, Darski found a genetic bone marrow match, and he then underwent treatment to receive a bone marrow transplant. He was let out of the hospital on 16 January 2011.