In Chaps.  2 and 3 , we have explored the themes of “basic fencing” and “complex fencing” with an evenly rotating formation based on the neighboring angle repulsion and input-to-state stability, respectively. Although Chaps.  2 and 3 addressed a moving target fencing and formation evolution, they only are applied to a constant-speed target. However, in practical applications, the varying-velocity target is more common, which has a more practical value in extremely dangerous situations. Therefore, this chapter continues to focus on the theme of “complex fencing”. Following the direction of the previous two chapters, we further propose a distributed controller via output regulation theory, which aims at solving a more general problem of cooperative fencing of targets with a time-varying velocity. In what follows, we will introduce the related background.