Avatar Buster

Korra, not prepared as she should have been, was defeated in battle of Zaofu and inprisoned by Kuvira in stone restraints. However, Kuvira couldnt afford to eliminate the avatar, she needed her alive as prisoner for propagation of her power. Instead the Great Uniter strapped Korra into leather bondage sleep sack, and moved her to a base where she is interogated. From there she's punished for "crimes against Great Uniter“. Kuvira even went so far as to invent what she called The Avatar Buster. Once Korra is inside, there's NO chance for Korra to escape. Luckily Korra´s friends hadn't said their last word...