I've been wanting to try this idea for an RP so I figured I'd see if anyone else was interested. But first some things about me:

~ I'm okay with short replies or longer ones but I won't do more than one paragraph per reply.
~ I'm alright with romance whether it's a major part of the RP or a subplot but it's not required to be included.
~ i'm open to whatever pairing should that be a factor.
~ I know minimal about the Korra series and I'm not a fan of it but that is the basis for the RP world. Will be explained later in post.
~ I do swear but if that bothers you say so and I'll filter it out as best I can.
~ I prefer PM RPs so I don't have to worry about upkeep of the thread but I am willing to do thread RPs
~ This would most likely be a darker RP, just as a warning.
~ I prefer OC but won't object to including cannon
~ As a fair warning, I don't like Korra, as a character. If you do let me know and I'll keep the mention of that to a minimum along with anything RP related that may involve her should she be included

The idea:
In the world of Avatar set in Korra times the 4 nations get along for the most part but still keep to themselves mostly, especially for marriage. But a few people do marry outside their own nation, resulting in interesting abilities. (Just think of Bolin's Lavabending for reference on that)
(That is where the idea actually starts)
A group of people is studying mixed benders, that is benders who have parents from different nations. Their study is harsh and cruel, pushing the benders to the limit of their strength and lives in some cases. They were forced into hiding when their study was discovered but they keep their horrid research going by kidnapping subjects or benders with single nation parents to test their skill as well.

Please post if this sounds interesting to you. I'll send you a PM and we can work out the details.