In this world, benders have 2-3 specialties. 1st is the elements-water, fire, air, earth. Next is one of the branches of any of these. If there is a third, it will be another, more complicated branch. If you have 4-5, you have potential to be the avatar. But that hasn't happened in years, so people have given up on that. It is rare for someone to only have their element as a specialty. A sure fire way to be the avatar is to be able to do more than one element. Now, other specialties probably won't come easily, cause that's not how that works. You can have a specialty that is branched from another element, but that's different. It usually means you have a knack for that sort of thing. Let's say, an Airbender can Metalbend. Metalbending deprives from Earthbending. You may have grown up with Earthbenders, because you may have seeped up the particles that make them Earthbenders, but you can't Earthbend.
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Love Live is the organization that manages idolbenders. Idols that also bend. So far, Love Live has been losing it's popularity because it hasn't had a avatar in the longest time. Well, it's not their fault. An avatar hasn't shown up in years. Since Korra actually. So, Love Live has decided to do something last resort-ish. Open a school to train children in bending, hoping to raise an avatar. In the end, Otonokizaka high school was opened. School of Idolbenders! Wanna fill out an application? It would help, since nobody has enrolled and they're running out of students. So, Kousaka Honoka opens another idol group, Muse. It consits of 9 girls, all hoping to be special. But, only 3 girls stand out...
Kousaka Honoka.
Yazawa Nico.
Koizumi Hanayo.
What's so special about them? Well, of course, the amount of skills they each have.
Honoka has 4.
Nico has 5.
Hanayo has 2.
So, who's the Avatar?