The Umbara race is simply an experiment gone wrong. A created disease by the mistake of an alchemist. The story was heard to be that a crazy old man got carried away with some genetic mutations. He decided to find the best specimen for his new found experiment. One which if he used wouldnt matter to the world. A tiny fairy was his prey. A young fairy boy with a rather large life to live by. He had gone about his days gathering food for his large family when he had been captured in a jar. Of course everyone knows how much Fairys hate jars so of course he had to put up a remote fight banging and screaming in his native tongue. He soon realized there was nothing he could do, soon the Old Alchemist gave him a chemical that made the boy pass out while he strapped him to a tiny table. A sick twisted grin crossed the old mans face as he injected the young boy with a powerful poison. The Old man was attempting to genetically turn him into a demon creature to do evils of the old mans wanting. In this case he had failed. The side effects of the poison had not turned the young boy evil, but one who fed from positive not negative energy. The old man was upset by this, but realize he had still created a poisoning disease one that can be manipulated if attempted. This made him content as he set him free. His mission to spread the poison. The fairy boy had not been normal after this, he had gained a beautiful more spirited voice, he soon realized that he had been made into a charmer, a siren rather.
With a single bite, no matter the beings size, would spread the poison. Having the abilities to charm you into sleep, hypnotize you, or even make you more relaxed. A more comical charm is that of infatuation, which lasts about an hour and can be used in help (as in to give someone courage) or mischief (make someone fall in love with something out of the ordinary for laughs) The effects of the disease more a positive then a negative. They can charm many things, the different the tune the more interesting the effects. They are even a bit elemental, with a certain tune they can create fire, freeze water, make a slight gust of wind. They can only make these elements present they cannot manipulate them.