The phrase "ultimate sacrifice" means giving up something extremely important or meaningful, often one's own life, for a greater cause or to help others. Full definition
However, Dimentio could never have predicted that the rekindled passion of Bleck and Tippi would restore all eight of the Pure Hearts, giving Mario and co. just enough power to defeat him, restore the rift in space and turn everything back to normal — save Bleck and Tippi, whose ultimate sacrifices of love would cost them their lives. (nintendojo.com)
The supposed ultimate sacrifice was a few days of suffering, and then ressurection into divinity. (religion.blogs.cnn.com)
We must honor the heroism and ultimate sacrifice rendered by both Officer Holder and his dedicated family, who have our prayers and thoughts at this time, and who will have the City's continuous support.» (queensbp.org)