The Apocalypse Knights is an order dedicated to maintaining order until the end of days. Once order is restored, the order must restore balance by introducing chaos. This must be repeated until all of the members are extinct, but everything else will be gone before it is time for these knights to be dismissed.
There is nothing that will keep an Apocalypse Knight from doing their duty until the world crumbles and all is ash. No obstacle, no man, nor beast can stop these creatures of both order and chaos, and order through chaos.