Baitoryu

Introduction
Baitoryu (literally meaning "Twice-sword Style") is a unique sword style that relies on duplicating any attack by creating a "force copy" that follows up a typical attack. It is more of a concept that simply boosts the user's basic attacks rather than a set list of moves. There are multiple ways for this attack duplication to be done: a Devil Fruit ability (Zei Zei no Mi), a fighting style (Merman Combat/Fish-Men Karate), or a simply using multiple precisely place Pound Cannons are all methods learning this style. Contrary to its misleading name, the style only requires one blade, and that blade does not have to be a sword, as seen with Telos and his shortspear.

History
It was originally developed by, the eater of the Zei Zei no Mi, and this style was supposed to be a mere supplement to her Devil Fruit's abilities. However, she realized that her Devil Fruit was not necessary to double her attacks, as mentioned above, so she decided to teach anyone who she thinks is a worthy student.