@Background Pony #F00E  
Rainbow Dash obviously. That’s also who she (and Rarity) got their whistles from too.

This “tribe” may not have been as isolated as supposed, since Swift Foot was on a mission to sabotage the Feat of Friendship not because they want revenge, but would prevent close relationships between the ponies and the other beings. Equestria has been deeply isolated from the rest of the world for a very long time, and this seemed to go very far back - in Season 8 we saw a deep abyss in Equestria between large parts of the ponies and non-ponies. There has been a red thread through MLP FiM about how the ponies behaved towards others, often seeing a xenophobic attitude rise to the surface.
 
For the thracians, Twilight Sparkle, with her policy of seeking friendship and close relationships with civilizations outside of equestria, may be perceived as a threat. It may mean that the Thracians may have hidden from the rest of Equestria, yet are integrated so that they may have strong interests in the country’s course. Also, they will be petty enough to seek revenge in the midst of this without the rest of Equestria getting wiser.
 
This is not unreasonable, Ian Flynn as writer for Sonic the Hegdehog was known for seemingly superficial narratives that hid great depths. Of course, he is known for his friend-turned-enemy stories that can sometimes be on the edge of what can be accepted. And this story slides right into the main thread of the story towards the end of FiM, how friendship are spread and embedded so that it becomes a force of nature that came to Twilight and her girlfriends in time of need.

@Toastypk  
Forget Thracians, I wanna know where the hay did applejack get that sunglasses

I wanna know more about the Thracians…

@PonyPon  
But jokes aside, I really hope we get to see their kingdom. I want to see how that place looks like.

@Background Pony #5DAE  
probably not just you.