...The once guard captain raised his sword "i died protecting you" says he. Now, accompanied by his fellow warriors, he marches to the besieged city. "Now, even in death i will uphold my oath". He looks at his undead comrades, "We will not rest until we have served our duty!" he yells. The guardsmen roar with recognition.
"We are not among the living, and hell will take us!" yells the guard captain. "...But we will drag our foes with us!" he thrusts his sword foreward and charges through the main gates...
Not my best story, but i did not have much info to build on.
It can vary, but I recall this desription being quite brief. Something along the lines of; show a Skeletal regiment in armour and carrying shields advancing on the viewer. the composition, colour choices, etc are all mine.