Mekki-Maru, as it appears in Soul Edge/Soul Blade.
It is a powerful weapon, but has the disadvantage in that it drains Taki's energy during battle, but it cannot cause a K.O. on its own.
It becomes Taki's standard weapon alongside Rekki-Maru in the Soul series. From then on it is spelled "Mekki-Maru", and plays a critical role in Taki's storyline.