Behind the Barrier BtB

Yuki wakes up in an unknown place 500 years after her last memory to find that humanity has all been wiped out. After being saved by the vampire Akaba, they discover a plot set by the queen of vampires to take over the world and kill everyone who opposes her. Now, they must team up and gather more allies to win the war against oppression and free themselves from the curse that's been laid on Japan.