J-Energy
J-Energy, sometimes called 'Jenergy', is an energy source generated within the bodies of Arothren, during life as well as after death in their coccooned state.
As Arothren are only known to live on the floating island of Frith, J-Energy-powered technology is also only found there. The base of Frith is, in fact, a huge J-Energy-powered levitation device powered by the enshrined coccooned remains of dead Arothren.
It is comparable to electricity in that it flows through a conductive circuit, however rather than electrons, it is a different type of particle found only in Frith-metals, known as J-particles that flow. Arothren absorb trace amounts of these metals from the water on Frith and incorporate them within their nervous system.