Y'shtola is a member of the Y tribe, obviously, however there is currently not much known about them. Y'shtola was also born in Sharlayan(?). I wonder when she joined the "Y" tribe. Was she born into it? Did she leave her original tribe to join the "Y"s?

When Seekers leave their tribe, such as assimilating into Hyur/Elezen cultures, they will lose their tribal letter. We see this in the Amal'jaa Beastyman quests with Loon Gah. She's a Seeker that left her tribe to help the Amal'jaa, in the process losing her tribal letter, so there is a precedent. Also, it's assumed the Miqo dancers in UD have lost their letters.

If Y'shtola is from Sharlayan, she should have either been born without a letter, or lost it when she moved to Sharlayan. Now, females go outside the tribe to have adventures and stuff, and in this way they do keep their tribal letters in the process, but Y'shtola's been gone for quite awhile, she should have lost her letter, right?

I wonder where the Y's are located.