The Broken Sky is on the main quest line of Horizon Forbidden West.
In The Broken Sky, we meet Tekotteh, a real winner. The chief is demanding Tekotteh dispatch challengers to a trial for warriors. Tekotteh does not want to. Our job is to make him comply.
I was nice enough to leave his people a cannon just in case anything showed up that was a threat to them. This quest is with Kotallo, and I like him.