Yuusha to Wagahai no Mujintou Hyouryuuki

The Great Demon King Veit and the hero Keel were facing their final battle at the Demon King's Castle. However, a cliff collapsed and they were washed ashore on a deserted island. Although the two were sworn enemies, they had to become friends in order to escape the island... Will the Great Demon King and the hero be able to connect with each other? (Source: Hakusensha, translated)