Board Thread:Theories and Speculation/@comment-5407586-20150624095943/@comment-2043993-20150624102526

Earth is definetly a component, since steel in the real world is Iron (naturrally occuring mineral) and Coal smacked together.

I'm in support of it being an advanced version of Earth release, but there's also the so far unexplored option of being a combination of Earth and Yin-Yang release, Yin- or Yang release (in which case the last option is my best guess).

That is if we're not talking Kekkei Tota of course, in which case I'm saying Earth + Fire + Lightning, it could also fit together with the novel where the users brother uses Fire and Earth release for Lava, I'm saying this because it's far from uncommon for siblings to share chakra natures