Complex sentence: At the end of the war D4Ys were still being used operationally against the U.S. Navy, and among the last of these were 11 aircraft led by Vice Admiral Matome Ugaki on a search mission on 15 August 1945, of which all but three were lost.
Split into simpler sentences: At the end of the war, D4Ys were still being used operationally against the U.S. Navy. Among the last of these were 11 aircraft led by Vice Admiral Matome Ugaki on a search mission on 15 August 1945, of which all but three were lost.