Elora's answer caused Emily to scoff as if annoyed at Elora's claim to superiority. "That still doesn't explain why you'd not only want this but apparently actively work towards it."
The fairy sighed and shrugged as if the answer was obvious. "And why wouldn't I? You and Emma are both talented and have rare affinities. Unfortunately, our current deal only lasts for ten years, which is barely a speck in our hopefully long lives."
An Arcanist's lifespan would increase exponentially with each rank they reach, and so, presumably, would a Runebound's. They couldn't actually be sure about shape-shifters and vampires yet, as aetherium hadn't been around long enough for them to reach such an age.
Still, considering the power of a Runebound body compared to that of an Arcanist, the assumption was that they would live even longer than Arcanists.