Yoru

Name Kokutou Yoru: The Black Blade Yoru

Yoru being 'night' and blade being 'katana'. It's also one of the 12 Saijou Oowazamono.

Owner

Dracule "Hawkeye" Mihawk

Known to be the strongest Sword in the world. It's an ornately decorated, man-sized (6 feet) sword shaped like a cross with a shiny black blade, curved at the end. It also seems to generate otherworldly purple streaks as it slices, as seen when he cut down Zoro and when he split Don Krieg's ship in half.