This is Mizumi

In summary, people often forget that size and strength, while important, are not the only factors that make a good swordsman. If you understand your blade, know your body, have enough strength and balance to master your tool, and can use reach to your advantage, you can surpass any opponent, regardless of their size. These are not my words, but those of Kanpeki, another very small duelist better known as the greatest swordsman of all time, and, if the signs are correct, reincarnated as Mizumi.