Demon Slayer: Kimetsu no Yaiba is a Japanese manga series written and illustrated by Koyoharu Gotouge.
The story takes place in Taishō-era Japan. It follows Tanjiro Kamado and his sister Nezuko Kamado as they seek a cure for Nezuko's demon curse. Tanjiro and Nezuko become entangled in the affairs of a secret society, known as the Demon Slayer Corps, that has been waging a secret war against demons for centuries. The demons are former humans who sold their humanity in exchange for power, and they feed on humans and possess supernatural abilities such as super strength, magic, and regeneration. Demons can only be killed if they're decapitated with weapons crafted from an alloy known as Sun Steel, injected with poison extracted from wisteria flowers, or exposed to sunlight. The Demon Slayers, on the other hand, are entirely human; however, they employ special breathing techniques, known as "Breathing Styles", which grant them superhuman strength and increased resistance. (Wikipedia direct reference)
Stinger Nichirin Katana: Shinobu carries a heavily modified Nichirin Katana forged by Tecchin Tecchikawahara  as her primary weapon.  Her katana's hilt is designed to bear resemblance to a four-petaled aqua / green coloured flower, trimmed with orange. The blade is black and silver  in colour, with the words Evil Demon (惡鬼 Akki) engraved on the right face, while the words Destruction (滅殺 Messatsu) are engraved on the left face due her sword's structure. Along with her katana, she has also modified the weapon's sheath, using it as a portable poison mixer and loader.
Her katana has a standard sword sheath that is deep black in colour with an orange pattern along its length and the blade is approximately 69 cm in length. The blade is a silver and black painted carbon steel.
The handle is painted red faux ray skin and is wrapped in a dark green coloured wrap and has orange metal alloy fittings.

Blade Length : 69 cm approx
Handle Length : 29cm approx
Overall Length : 105 cm approx