She is a relatively young elementarist mage of friendly nature.
She is very curious (mostly about how stuff works, not other peoples' private lives), and can happily talk about languages, magic, plants, animals, odd places...
Politeness and basic manners are a matter of course for her, but formal situations with complex protocol make her nervous. It also seems like she doesn't know about shaking hands.
Nearly all of her clothing is dark blue (a colour restricted to magic-users where she comes from), often with yellow decorations. She carries a shoulder-height staff (polished wood without ornaments) which can act as focus for some of her spells.
She has a decent foundation of school knowledge (but the history, geography and language bits would be of little use here...), but most of her skills lie with magic.
She can also manipulate water and soil on a smaller scale. Air mostly eludes her, though she has been improving on sound manipulation. She can work rock if she pushes herself. The only thing she can to with metal is detecting where it is, and metal, particularly iron, can block her magic.
Sylvie channels through her palms and fingers. She uses simple gestures, some subtle enough that that they don't stand out.
You can find more detailed notes [[my own wiki]].
To someone who can see magic, Sylvie working any would be visible as something like tendrils or thin tentacles emerging from her palms or fingers, and touching and sinking into what she was examining or manipulating.
She worked for a while as gardener at the Unnamed Inn, making the acquaintance of Suitov, Jaina Jade, Basaltine, and Weft - possibly others. Jaina introduced her to Lance.
Nico and Sylvie left the Cross'd Roads and travelled together for a while, growing relatively close.
She has grown rather attached to Sebastian, despite his twisty morals and bothersome patron deities. They have a lot in common, including feeling lost, weird senses of humour, and active libidos.
Weft confuses her. She had been told he's a murderer, and she saw that he was rather keen on killing a certain griffin-like creature, but on the other hand he'd been obviously concerned about Sebastian, and rather friendly when things calmed down.
Suitov seems like a kindred spirit in that he's curious. On some level his relatively formal manner makes her feel awkward.
Later she did quite a bit of travelling, which is not unusual for young mages.
One job she was given due to her feeling comfortable in the wild would have been obtaining an egg of a small dragon to an older mage, who wanted to make a dragon his familiar. This job was, however, a failure, since the dragon hatched before it could be delivered. Sylvie named it Ayu-Asra and is stuck with it. If someone assumes he was her familiar, she corrects them; he is just a pet.