Fallen: The Founder's Seed, Book 1, livre audio

When humans attack Iridos, killing most of the unammi population, misfit cleric Alira discovers she is a Harvester, able to absorb the memories and personalities of those who die in her presence. She’ll need that knowledge to help her people. The problem is, not all Harvesters survive with their minds intact.
Alira knows the pilots—including her brother—who live among the humans will be the next target for enemies of the unammi, unless someone flies to the nearest colony world to warn them of the threat. And since Alira Harvested the last pilot on Iridos, she’s the only one who can do it. If she leaves, she’ll be outcast. If she doesn’t, her brother and the other pilots will die. To Alira, there’s no choice. She’s never going to fit in anyway.
As a shapeshifter, looking human is easy. Acting human is far more difficult, especially once her Harvests start arguing in her head. But she has to succeed. If her species is to have any chance at survival, Alira must take the form of her nemesis, Harvest souls never intended for her, and shelter the remnants of her race where her enemies would never look, in a place only a lunatic would go. Can she succeed without going insane?