I'm not overtly trying to make this similar to Borderlands but here is the version of what the Siren Class is depicted here in Runa (in my POV):
Sirens can be of any species-and a female only class. They are women who have been given the special privilege of being able to sense and control magic. However-most cases the woman in question cannot siphon the magic that is naturally being created by the world around them-and are in need of a "Magic Tech Generator". The generator is not a rare object-simply any metallic device that has a window to allow the naturally occurring magic to flow through. The device allows for the storing of "Magic Techs" based more or less upon six elements: Earth, Fire, Wind, Water, Ice, and Lightning. There are more than those six out in the world-some darker and even more so deadly than others.
However-there prolonged use of Magic Generators will physically change the user. The usual cases are that the woman's skin grows a grey shade paler, yellow/gold eyes, and a blue tattoo that runs up one side of the body with the exception of the face. The process can take four months to become fully a Siren in appearance. In some rare cases, I mean REALLY RARE cases, the woman in question will become "one" with her natural element and will physically become one with their special element.
Though, for the reasons listed above-most common people live in fear of Sirens, especially the Droxis Democracy. The Sirens are nicknamed as being 'Bewitched' and considered a force not to reckon with. Most Sirens are driven out of the towns they were born in-while others were unfortunate not to and were executed or imprisoned unjustly.
Sirens can use magic to aid themselves or allies; and or ail their enemies and monsters that roam in the plains.
Another interesting fact-is once you've become a Siren, your a Siren for the rest of your life-even if the magic generator is destroyed or stolen. Though there are some rumors...
(refer to my profile for magic tech skills ideas)