She writes most of the lyrics and sings almost all of them. She notices things other people decide not to say, and says them anyway. She has a gift for the precise word for an uncomfortable feeling.
Real name Adrian, Mage composes most of the music. He plays guitar and keys and somehow performs most of the production wizardry, much to the quiet mystification of the others. He has strong opinions about sound and very few opinions about what counts as an instrument.
With a classical music education as part of his formidable training, Ronan plays bass and whatever else the song needs with startlingly near-military precision.
Drums and percussion. Not just one thing, not just one way, not just one sound if a different one is available. He contributes vocals occasionally. Usually somewhere you didn't expect them.