Swordstaff
Ryu fell into his thoughts.
"The swordstaff…"
As a Ruin Master, there were very few staples of history that Ryu wasn't aware of. The swordstaff was an ancient weapon that didn't get much attention during later Eras.
In the past, polearm weapons were the norm, at least for the Shrine Plane. This was because beasts were the rulers. Facing enemies with such large bodies, humans had to take advantage of whatever they could. As a result, polearm weapons were created.
Over time, the swordstaff evolved into the spear, glaive, halberd, and other more common polearms. As for the reason it was forgotten, it was quite simple. The swordstaff was good at many things, but not perfect at any one thing.