We've nearly all played games. Board games, video games, playground games. One thing all games have in common is rules. In tag you're "it" if you get touched, in baseball you score a home run by clearing all the bases without getting touched "out". Rules help the games flow and provide structure to play.
In many games, if not most, even those tasked with overseeing the game play such as a referee are not "rulers". They too follow their own rules for applying and making sure the other rules are followed. Games are "rules with no rulers".
We thrive when we are not ruled but play by rules. It allows sports, tabletop games, and more to be played and enjoyed by many of us. Yet we don't need a emperor. Players help to keep each other honest by using the rules as a touchstone to guide game play.
This is the concept behind Anarchy-X's "without rulers". We need no royalty to cooperate and function as a society. We need no rulers, only rules we can agree on and use to keep each other together in our play. Just like "house rules" for board games, we can all agree when a rule doesn't make sense for us anymore or when we need to adopt a new rule. This is the role of democracy.
Through the democratic process we can collectively make the rules, replacing the ruler with society as a whole. We can create rules but need no ruler. We need no king.