Her new splash art shows her in Ionia. pretty sure her old one did too.
http://4.bp.blogspot.com/-UsfBupymiM...a_Splash_0.jpg
also, were her parents Ionian? She was left in an Ionian adoption house, but Lestara was Demacian and had to at least have known her parents to know the Etwhal by description

She was found abandoned at an Ionian adoption house, so I assume she's Ionian

Ionian but moved to Demacia right?

She was born in Ionia, but was adopted and moved to Demacia.

i was gonna make this thread

I wonder if they count her as a champion for Demacia or a champion of Ionia though

She's Ionian.

We know nothing about her biological parents, so she could even be from Shadow Isles (lol, that'd be funny).

Seriously speaking, an article from the JoJ, about her concert in an Ionian celebration, refers to her as a Demacian musician. I don't know which article had this but it was one of the oldest ones, as I remember it mention she played her latest song: Aria of Perseverance (that's her W, for those who don't play with her).