What to do with the "Evil Races"

Okay, so I have a possibility of 2 antagonistic races:
- The Lavothian from RHB p.105
- The Sathar from FE#23 p.30

Or I could simply create one or more using the Alien Species Generation Rules on pp.98-103 of the RHB...

I was thinking of having one race be on one side of the Frontier ("off-map"?), and the other on another side, like East/West or maybe North/South...

Looking at the map of the Frontier on pp.198-199 of the PHB is that the North-East section is a good place for one of the species, and to the West, there is pretty much the whole Western Edge, a vast majority of the Southern Edge, and about half of the Norther edge available for the other species...

I could use on of the "edge systems" for them, or perhaps even create new ones... (If I chose one of the existing systems, I should probably wait and see which one I assign to the converted Star Frontier player races and the other playable races from the RHB. Since Sathar can also speak Yazirian, I'll have to put the Yazirian relatively close to the area of space claimed by the Sathar... The two planets to the right of the Yar Clanarchy? If I do that, I might have to slightly modify the Sathar so they also speak Yar... (Hum, no, don't know where I've seen that...) Hmm, hey, wait just a darn minute, there's a planet inside the Nagol Dust Clouds! That could be interesting...)

Or what if I put the Sathar off-map South, and the Yazirian homeworld on the unmarked planet between the Microtia and Neriph systems (the one left of the Great Wall)? If I put the Lavothian somewhere West of there, it does raise the interesting concept of a Sathar-Lavothian conflict, which could be a nice idea for a future scenario... Or even worse, a Sathar-Lavothian alliance... Though, judging by the description of both species, this would be rather unlikely...