Vampire People

Sometimes, Terran humans undertook "great change" as a society, with everyone, or nearly everyone using genetic modifications that dramatically changed the physical appearances of the individual members of the population. These genetic changes allowed them to become distinct from lower-tech time travelers, and many times were used to make it easier to kill, maim, or defeat, arriving time travelers, physically, at least.

In some times, Terran human populations used society-wide genetic modification techniques to become "Vampire People".

See: Daybreakers, Blade, Blade II, Blade Trinity, Dead Times: Vampires, Cat People