- "Congratulations on being named center striker."
- ―Merei Spanjaf to Zare Leonis
Center striker was one of six positions in the sport of grav-ball. It was generally considered the game's key position, as the center striker began every play and had the choice in each play of running with the ball, passing it one of the two strikers, or handing it off to one of the two fullbacks for a carry. While these parameters gave the center striker a lot of importance in the game, there were certain limits. For example, the center striker was never allowed to enter the game's scoring area, even if he or she was carrying the ball.
Zare Leonis was chosen as the center striker for the AppSci SaberCats. Due to the center striker's key role, Leonis often had to improvise strategy on the fly and call plays. Only one "coach's time out" was permitted in each triad of the game, with much of the duties that would normally be given to a coach instead falling to the center striker. As such, Leonis's role as center striker made him the de facto team captain.
- Servants of the Empire: Edge of the Galaxy (First appearance)
- Servants of the Empire: Rebel in the Ranks (Mentioned only)
- Servants of the Empire: The Secret Academy (Mentioned only)