The Final Fortress (ファイナルフォートレス Fainarufōtoresu,Final Fortress?) is a giant whale shark-shaped battle flagship that makes its first appearance in Sonic Heroes as the final stage. Final Fortress is located in the heart of the Egg Fleet, and seems to be permanently surrounded by rough weather.
In Sonic Heroes, Final Fortress acts as the final stage of the game. It has many different sections crossed with grindingrails, Tornado Jump poles, cannon fire, and the best of Dr. Eggman's robotic army. Some parts of the stage collapse; others can be detonated. Laser fire occurs periodically throughout the stage as well. In the very core of the flagship lies a giant structure with a mechanical version of Eggman's head on top, hiding the power core of the vessel. The most common robot there is the E-2000. Team Sonic must take down the battleship by destroying its power core. Team Dark must reach this power core and capture the Doctor. Team Rose goes to find Froggy and Chocola, whom they believe have been kidnapped by Eggman. Team Chaotix goes to find the Keys to free their client and meet him in person. After reaching the core, Neo Metal Sonic, disguised as Eggman, attempts to finish off the heroes in the Egg Emperor.
The following is a list of requirements to attain a rank for each mission with each team.
Destroy the flagship's core!
Get to the core where Eggman is!
Hurry and find Eggman!
Find the keys to the cell where the client is locked up!
In Team Sonic Racing, the Final Fortress appears as the final location in the game and serves as Eggman's main base in the story mode. It has three racetracks, each of which explore different aspects of the location.
During the events of the game, the Final Fortress served as the main base of Dr. Eggman's, who was being accompanied by Orbot, Cubot, Zavok and Metal Sonic. After Dr. Eggman learned that Dodon Pa had constructed the Ultimate Energy Engine, he kidnapped Dodon Pa and brought him to the Final Fortress where he had him work on completing the engine. Sonic and his friends eventually arrived on the Final Fortress and faced Eggman and his henchmen several times in order to save Dodon Pa, not knowing that they were helping Eggman and Dodon Pa complete the engine. After the engine was finally complete, Eggman stole it and used it to power his monster machine. However, the monster machine soon went crazy and destroyed the energy core onboard the Final Fortress. While Eggman and his henchmen fled the airship, Sonic and his friends saved Dodon Pa. With the destruction of Final Fortress however, the cars that Dodon Pa donated to Sonic and his friends were destroyed as well. As thanks to the heroes for saving his life however, Dodon Pa promised that he would prepare new cars for them all.
In Super Hard Mode, after Team Sonic triggers the first self-destruct button onto the rail section, Sonic comments about the dark clouds in the background while Knuckles asks Tails if he can handle the stormy weather. Tails falsely replies that he is not scared, alluding to the fact that Tails has a fear of lightning.
In Team Sonic's version of Final Fortress, Tails will ask why the ship self-destructed after pressing the button in the English version while in the Japanese version, Tails asked why Eggman would place a self-destruct switch where it was easily accessible.
Though surrounded by a massive thunderstorm in this stage, it can be seen in clear weather during the Egg Fleet opening cutscene.