On Christmas morning, Sirius recovers enough to reveal the horrific details of his torture to Dumbledore and Moody. At a Black family Christmas Eve gathering attended by Death Eaters, Bellatrix Lestrange showed her Dark Mark and demanded Sirius swear allegiance to Voldemort. When he refused repeatedly, his own parents took turns torturing him with the Cruciatus curse while family members including Regulus watched helplessly. Sirius managed to escape through the library fireplace after the torture stopped, with his brother secretly helping by sending the warning owl. The revelation cements his permanent adoption into the Potter family while highlighting the complete breakdown of his birth family.