Yukio Mishima
I was never enamored of his fiction (I've read more biographies of Mishima than novels by him), but Yukio Mishima lived one of the most fascinating lives of the mid 20th century, culminating in his suicide:
With a prepared manifesto and banner listing their demands, Mishima stepped onto the balcony to address the soldiers gathered below. His speech was intended to inspire a coup d'état restoring the powers of the emperor. He succeeded only in irritating them, however, and was mocked and jeered. He finished his planned speech after a few minutes, returned to the commandant's office and committed seppuku.
I was surprised to find this video with Mishima speaking English. I had thought his English rudimentary, but it's actually quite good.
Some classic photos.