Lust, Harem, and the Dead

What would happen if Takashi Komuro and Saeko Busujima, were bisexual and both had a heram of male and female students from their school, and any other (teenage or young adult) survivor they crossed paths. With Takashi's heroic personality and leadership skills and Seako's big sister aruoa and her excellent combat skills it is no wonder why sooo many of their classmates wouldn't mind sharing.