inertia sufficient to prize apart armor -
????
Its not ideal for humans. Not by any measure.But Fyunnen are somewhere around 340-500% stronger than humans are - solving the problem of lifting a solid metal weapon above shoulder height. Its really the logical extension of half-swording - the style of holding a handle in your dominant hand and then through cloth or gauntlet, holding the blade itself against your palm so you can grapple, slam and shunt like a spear. The most famous example on record is the zweihander, which in spite of what Dark Souls players would like to think is not a "god tier sword" -- but a sword that can be used as a spear and grappled with like a spear because it has a second cross-guard and an intentionally blunted section for that kind of handling.
In this sense, a fura is about swinging from the hips and digging your feet into the ground for slow aggressive attacks that use sheer force to smash down armored opponents - or lining it up like a spear and pistoning it through the forward hand in a stabbing motion.
Anyway, its basically a spear for people who are much stronger than humans. Lots of weapons can't exist because lifting a solid metal weapon above your shoulder height is really difficult. This... Not so much, given Fyunnen are using it.
Japan actually has something similar in its history used called an ooken (大剣) that's primarily bastardized by fantasy into what we know today as a 'buster sword' but classically, it was a thin flat blade called an adapted
Zanbatō that doubled as a shield. Fantasy took the concept further, calling up the need for a counterweight. Here, that counterweight is another sword, and a handle that's over most of the length.
Unlike the useless bat'leth who's inwardly shaped blade with a free moving elbow (unlike say an Indian Kora or particularly the kirpan which used the forward curve to great effect by having the pommel lock the wrist up to provide driving force - which later became the kukuri), the fura doesn't have the weakness of an elbow free curve because its two solid pieces and there's a counterweight that can be moved from one side to the other, adjusting how it swings - and in the process, the placement of the handle.
Keep in mind this is from an era where the use of steam through the use of nuclear heating implements was perfected yet gunpowder was unreliable due to the strange shipping practices and the fact it tended to go up in flames regularly - being unreliable as Lor's atmosphere oxidized gunpowder very quickly until it stabilized about the time Lor went underground. As a result, you get knights who use high pressure steam in their armor a a kind of thruster for longer jumps and assisted swings.
Lor got on the nuclear energy boat very very early because of
natural 'reactors' in the planet's crust that were studied and replicated: they didn't understand the physics - just that it worked.
