Is The Last Story first party or third party?

[Wright]

Ryudo said:

No. Nintendo owns it. Mistwalker is like Treasure where the publisher owns the IP. Microsoft Owns Blue Dragon and Lost Odessey.

I just checked the link someone else provided here. As I expected, neither Nintendo nor Microsoft has total control over Mistwalker's IPs. So while they aren't entirely property of Mistwalker, they aren't Nintendo's either.