The first work in the series in chronological order would be My Dragon System, set during the Magical Era of Earth. Then, there are Level up Zombie! and My Werewolf System that happen during the Magicless Era of Earth. Finally, My Vampire System is set in the 27th century, during a truce just after the First Dalki War that led to the extermination of humanity and the destruction of the world of the Magicless Era.
Virtual Sword God! has a conflicting canonicity with the other works, but if it could be included in the same world, it would likely happen during the generation just before the First Dalki War, so before My Vampire System.
