Seyin |16 No affiliated nation spirit guide

Seyin is a spirit guide, an occupation created by a previous avatar (likely from the air nomads) who try to keep the balance between the spirit world and the physical world during the period of time when the current avatar dies up until the announcement of the new avatar. They then give up their position - only taking it up again once the avatar dies.

Due to Aang being in the iceberg for 100 years and the war there aren't many spirit guides left. And those who are left aren't as effective due to the avatar's absence (spirits are getting restless without the avatar to keep balance)

Seyin is very proper and respectful. She has a hard time relaxing and acting her age, as growing up her father never gave her a chance to be a kid. She has been on her own for the past 5 years.

She initially meets Prince Zuko and Uncle Iroh at a port in the Earth Kingdom. Iroh immediately recognizes Seyin as a spirit guide (due to his own history with the spirit world) and have a pleasant chat.

She then meets with the Gaang, stays with them for a bit on their journey to the north pole (she has never been but has heard about the north pole's great spiritual connection!) before leaving after witnessing a hostile spirit attack at a village. She feels her duty must be towards maintaining the balance while Aang focuses on mastering the 4 elements.

After the attack on the north pole Seyin eventually meets up with a lone Zuko. She can tell he's going through a difficult time and tries to offer her support. Zuko rebuffs her but she is pretty insistent and he ends up having a meal with her.