The Final Fortress (最終的な要塞,Saishū Teki na Yōsai?) is a giant whale shark-shaped battle flagship that makes its first appearance in Sonic Heroes as the final stage, and as three different racing tracks in the racing game Sonic & Sega All-Stars Racing. Final Fortress is located in the heart of the Egg Fleet, and seems to be permanently surrounded in rough weather. Modern Sonic fights the Egg Emperor in Final Fortress in the Nintendo 3DS version of Sonic Generations.
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 Doctor Eggman's robotic army. Some parts of the stage collapse; others can be detonated. Laser fire occurs periodically throughout the stage, probably as a security reflex. 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 befall 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, Eggman goes to finish off the heroes in his most powerful robot yet.
Final Fortress returns as the battlefield where Modern Sonic faces the Egg Emperor in the Modern Era for the Nintendo 3DS version of the game.
In Super Hard Mode, after Team Sonic triggers the first self-destruct button onto the rail section, Sonic comments that the clouds are dark and Knuckles asks Tails if he can handle the stormy weather. Tails falsely replies that he's not scared, although, there was a slight pause before he finished his sentence, alluding to the fact that Tails has a fear of lightning.
In Team Sonic's version of Final Fortress, shortly after destroying the first ship, there is a mistranslation. In the English version, Tails will ask why the ship self-destructed after pressing the button. In the Japanese version of the line, Tails asked why Eggman would place a self destruct switch where it was easily accessible.
Whenever the lasers fire, Tails will say "Blue/Yellow/Red laser fired!" which does not make a lot of sense if thought carefully. It would make sense if he says "Blue/Yellow/Red laser firing!".
Rouge also says "Yellow laser fired!" but says something different for the other lasers.
The sky of Final Fortress.
The big sky texture is used in unknown objects or worlds.
The small sky texture which is used on skies in Final Fortress