Talk:Avatar/@comment-4991841-20120628171752/@comment-86.95.184.88-20120710213903

As an Avatar you master all 4 elements + energybending (which is not practised by all Avatars). As you have seen, teaching all 4 bending disciplines takes years of practice and discipline; it took Roku 12-years to master air-, water- and earthbending. And as a 16-year old he was still training his firebending I assume. Mastering all sub-techniques like lightning-, metal- and bloodbending requires more discipline and practise and more years of enhancing your skills. Thereby an expert bender still controlls only 1 element and his/her only sources of extra power are events like a full moon (in case of waterbenders) or the passing of a comet (in case of firebenders). This outmaches an expert bender by a fully-realised Avatar who masters all elements. In this case it's probably not worth the efford and time of the Avatar to master the subtechniques.

Thereby it's not known whether Aang has mastered metalbending and lightningbending in a later future. And Korra is still young enough to teach metal-, lightning- and bloodbending.

And I find it very unlikely that past Avatars haven't practised and mastered the sub-techniques of the bending arts.(except blood- and metalbending off course)