Hadesari didn't participate much in the Creation of the Races, having so much already to deal with by managing a whole underworld. However, he did get bored with just souls and zombies to be the patron of, so he created the Bloodless out of seemingly pure boredom. He asked Wintaer if he could borrow some humans and began to experiment. He drained their blood to make them dead, but then got swarmed suddenly with the arrival of the first dead crop of Humans and Dri'in from the First Wars that he forgot all about them. What was left in his little workshop were undead creatures without blood carousing through their veins. The Age of Creation was a strange time, and, by fiddling around in the workshop, these abandoned Humans found a way to sustain life: by feeding off the blood of normal Humans and filling their veins with that! Through time, not only Humans became Bloodless. Other Bloodless were created in an "exchange of blood." Should a Bloodless take the blood of another and then feed that blood back to the person it came from, that person will become a Bloodless, too. There is a chemical in the Bloodless body that acts as an agent for the change, to drain the blood out of an individual and equip them with the ability to transport sucked blood into the system. Blood from the same species as what the Bloodless used to be is more effective than other species' vital fluids. Unlike the vampires of other worlds, a Bloodless is NOT immortal, although they maintain youth rather well. A small child turned into a Bloodless at a young age will still grow to be a young woman or man, but they will not become old. Scientists are still trying to find out why. Also, unlike vampires, they are quite able to experience sunlight, although they can not feed effectively during the day. They will get terribly sick and the blood won't transfer to the veins.
It is nearly impossible to tell a Bloodless from their respectable origin race, unless you got a look at their mouth. They have, of course, fangs to aid them in creating a cut to drink from. Also, they might seem unnaturally pale if they haven't had a drink in a while, since their source of blood is running out and their veins emptying.
As for locations, Bloodless could be anywhere. They can also take on occupations and classes that they could have had when they were "normal," with the exception of Majani. But, if they should drink from a Majani, having their blood inside of them enables them to temporarily have the abilities that that Majani did.