Purple pelts, forming the symbol of the Sleep Rune, derive from a rare flower whose smell causes almost every living being to fall into a deep slumber, occurred as well when the Wind of Sleep spell used by the Wind Rune is performed. This rune lulls the target sometimes to sleep immediately, when a direct attack strikes onto it.
The sleep status makes sure the sleeper is caught off guard in the future, as he takes more damage done by further physical attacks. However, sustained hits tend to wake him up sooner or later.
The dancer Karen used the Sleep Runes power during the Dunan Unification War in order to prevent the growing of grass under one's feet with the additional help of her Twin Ring Rune, while the other foes were asleep already. - Celes