Raylight for TES V: Skyrim

A katana that has fancy effects, staggers on every hit, has higher damage than the dragonbone sword, and believe it or not, it has a sheath! OMG!

The sword can be found in a cellar behind the Guard Barracks in Whiterun, there's also a screenshot that shows the exact location, as well as a video.
Alternatively you can obtain it by using this console command: player.additem 2E000D63 1

No DLCs required, and there should be no compatibility issues.

Author:  HakitoJin

Tag: Swords