The first human who noticed that Shiki's can burn in anime was Toshio Ozaki. In episode 14 during the daylight, he noticed that the dead body of his wife stated to burn. He quickly took her away to operatuib room where there was no sunlight. In the first OVA episode when the Humans ran out of their Stakes, they had an idea to pull all last Shikis from the pipelines outside. When sun got up all the Shikis from the pipelines started burn.