Egg Emperor is the final boss of Sonic Heroes' main story and it takes place after completing the Final Fortress. This robot is in the form of a knight. At some point on the Egg Fleet, each of the teams confront Dr. Eggman, who is piloting the Egg Emperor, one last time in this battle.
 Boss Battle
This boss battle begins with the teams giving chase to the Egg Emperor. While chasing the boss, teams must also avoid Eggman's robots, as well as the cannons that are targeting them. There are Power Cores throughout the course battle, which teams can obtain to increase their power.
The Egg Emperor has some attacks of its own, such as swinging its lance, which results in vertical or horizontal laser blasts, and launching missiles, which homes in on the team. Also, if you let the Egg Emperor get too far, he will attempt to charge towards you, an attack which is unstoppable.
The Egg Emperor's weakpoint is the glowing orb on its chest. While chasing it, the best way to attack is using Tails' Thundershoot, which will automatically strike the weakpoint if you're close.
Eventually the battle will reach a large circular arena, where Eggman will remain in the center and launch the same attacks. Also in this arena are the Eggman robots and cannons, which teams can defeat to make the battle with the boss much easier. You can continue striking Eggman with Tails Thundershoot, which is the most effective way, or using any of Knuckles and Sonic's attacks. Team Blast, if the gauge is full, is another effective way of removing a large portion of the Egg Emperor's health.
After a period of time, the Egg Emperor will leave the arena, and the teams must give it chase once again. This process will repeat until you've depleted all of his health(150 HP).
 Sonic Generations
The Egg Emperor reappears in the 3DS version of Sonic Generations. This boss is in the Modern Era and it's played, using Modern Sonic.
The battle begins with Sonic giving chase to the Egg Emperor in a circular arena. He must avoid the robot's laser blast from its lance, as well as the cannons in the background that are launching missiles at you. After dodging them and striking the robot, it will proceded to the center, where Sonic will boost his way to the inner arena. In this portion, you can destroy the cannons, but the main objective is to wait until the Egg Emperor charges towards you. When it does, you must dodge then quickly strike back by boosting into him.
After a few hits, the Egg Emperor proceeds back to the area where the battle first began. You must repeat the process once more. When the robot proceeds back into the inner arena, you must avoid the quick laser blasts that the Egg Emperor will launch towards you. Afterwards, it will attempt to charge in your direction. Dodge it, and strike the Egg Emperor a couple more times to defeat it.