This one is tricky.
The aeon-lich is an extraplanar immortal being who has stood as a guardian of the world for centuries. It can't speak, instead it transfers understanding directly into the brain and memory of people he's talking to. This ability and mode of communication is called "advanced envisioning". So, this role is not to voice the aeon-lich, this role is to voice the narrator whose voice is used to describe this advanced envisioning.
The text of the lines describes what the heroes believe, as this belief is being created in their heads.
Ultimately, you're a narrator, as if reading lines in a book, but you're far from dispassionate. The aeon-lich transfers not just knowledge but also emotion and shapes how the heroes think and feel about him. Your voice is how we'll translate the emotion so that players themselves can sense it.
Your voice would ideally evoke a sense of mystery, inevitability, confidence, and would provoke slight unease, confusion and discomfort in the listener at this strange mode of communication.
16 lines, total compensation $48