It wouldn't make sense as a craftable until it was introduced to the game as something viable in the world. There would need to be a legit reason to introduce it as a wearable item, other than it looking cool or tough or whatever. OP needs to make his designs make sense in the world. They aren't terrible ideas or designs, but they need to fit. It needs to work somehow into the game. Seeing as it is a fantasy game, it would take some real creativity on the team's part to come up with an idea on how it would work.