nibRunes is a lightweight (20kb) and simple DK Rune display, which comes with an in-built Combat Fader.
All options can be adjusted at the top of Config.lua
After changing settings, type: /reload ui
Note: By default, the Rune display will be completely hidden when you are out of combat, have no enemy target, and all your runes are full. When changing settings, simply target a Training Dummy to bring up the Rune display.