A gestalt item quarterstaff.
The history of the Nyoi-bō is a very long one. The oldest stories tell a story not of a a great weapon but a pillar that held up a great observatory that a group of mysterious guardians used long ago. Not much is know about these great guardians except that they once were there to protect Ilfrean. This all comes from the legend of master Mutaito it is said he found it when he was battling a mighty monster in the ruins of a guardian building. It was said that master Mutaito was the greatest fighter of his time.
It was hard to confirm this story but one story is known of how master Mutaito defeated an unbeatable monster that came to destroy the lands he lived in. It is here that the legend of Mutaito took of when he and his two greatest students the Kamesennin and the Tsurusennin fought and defeted this monster. his students tell of there master always being where the monster did not expect him creating openings for the two students to pummel the creature. The battle ended when Master Mutaito finally managed to crush the the creature head with a strike of Nyoi-bō but not before he he himself was fatally wounded as well.
It was here that both students decided that they would go on and create there own schools and that the last thing they would do together was create a shrine for their masters body to rest in forever. And that they would place his staff until a wielder worthy of the weapon would be found. They then hide the place and only those who were worthy could enter if they had the right knowledge. There the Nyoi-bō waits for its next owner to wield it. They wrote down the secret to the entrance of the shrine on the Kamesennin's signature turtle shell but in such a way that it could only be read by looking trough the lens of the Tsurusennin's crane amulet.
Wakibara 脇腹: The wielder of Nyoi-bō can flank enemies from seemingly impossible angles. He can designate any adjacent square as the square from which flanking against an ally is determined (including the square where he stands, as normal). He can designate the square at the beginning of his turn or at any time during his turn. The designated square remains his effective square for flanking until he is no longer adjacent to it or until he chooses a different square (at the start of one of his turns). The wielder can even choose a square that is impassable or occupied.
Nobiagaru 伸び上がる: This is the reason why the Nyoi-bō was used as a pillar for a observatory. It change change in length from around 4 inches to 20 feet in length. Originally this allowed to observatory to reach the optimal hight but now it is used to strike opponents at a distance. This allows the weapon to once per turn as a free action to change its length. This allows Nyoi-bō to switch between a reach weapon or a normal length quarterstaff.
Tetsu burō 鉄ブロー: The power of Nyoi-bō's wielder is channelled trough itself this allows the powers of Ki Strike (Su) and the Unarmed Strike to work right trough the weapon. This allows it to hit much harder then a quarterstaff of such a size and weight should do.