Starting off rather simple, Steel is an advanced element which comes from the earth, and it is believed or I would almost say it is a statement that it is made up of earth and fire. This due to earth being the component where earthen materials come from, while fire is used to mould and change it, where it makes sense due to the process of making steel in real life this seems like the only plausible explanation. Now, steel is a very strong element in itself, which is strong towards water, while it is weak to lightning, obviously showing that lightning can easily blast through it. However, we can also talk about the forms of steel that there are, where at least in the beginning the most common form of steel was the coating of one's self in a a shell of metal. There was someone known whom had a malleable form of liquid steel which could be harden or soften at will. I do not know if this is the case of it here on NB if that is possible or not, that is a question id like answered. Of course you can make your own steel or control existing steel. I do think that is what I know