I'm also still trying to put a finger on Savoulain's character beats in general - I feel like I know what they are, but pinning the words down is another story. A haphazard collection of attempts:
- Struggling with a profound feeling of detachment from a world that you've only been able to see and not touch. Loving the world, and yet being alien to it. Being caught between here and elsewhere.
- Figuring out how you become part of the world. The gulf from knowing to doing to participating, bridged by making connections with others.
- Coming to terms with your limitations; learning to be imperfect, and accept help from others.
The alternate, RP-friendly backstory I'm rolling around is that Savoulain is an otherwise ordinary Sharlayan who awakened to the Echo at a young age - so strongly so that it became debilitating, and resulted in him growing up very isolated. He eventually did learn how to manage the Echo to the point that he can function in the wider world, and ended up attending the Studium and all that. However, while he's a very kind and well-spoken person, he's still easily overwhelmed and kind of closed off from others due to his childhood and the ongoing background noise of the Echo.
Lucent probably meets him at the Studium, and they become friends over the course of their years there. (Sav probably studies aetherology with a side of arcanima, so they have a lot to talk about!) By the time post-Endwalker rolls around, they've been together for a while.