M21: The Core is the 21st and penultimate mission in Metroid Prime: Federation Force, and the final mission set on Talvania. Having detected a third and final transfer device on Talvania, General Alex Miles orders the Federation Force to destroy the device, so that the Galactic Federation can finally locate the Doomseye, the Pirates' secret weapon.
The Force begins on a large platform in the gas clouds of Talvania, with a zipline leading into the central control tower. The first part of the interior facility is guarded by Grim-Class Turrets and Security Bots. Further inside, the Force is locked inside a chamber where a Mainframe attacks them. The mission's bonus objective is to take no damage from its lasers. After the Mainframe is destroyed, it will leave a large crater that the Marines can descend. Not much farther on is the transfer device room, which is guarded by spawning Pirate Troopers and Armored Bots. The device's destruction completes the mission, and unmasks the Doomseye.
Pirate Log: Transfer Device
Only one transfer device remains operational. Maximize power transmission at once due to the loss of the other devices.
"We received word from the intelligence team that they've succeeded in decrypting the entire encrypted message from the Space Pirates.
According to the final account of the message's contents, there are a total of three transfer devices. Each planet in the Bermuda system had one on it.
This tower was built by the machine race of Talvania. Despite being so old, it appears to still have a functioning security system.
Also, although we've nearly eliminated the Space Pirate presence from the planet, there may still be some hiding in the tower. Be careful.
The Federation fleet is fast approaching, Marine. Get in that tower, locate the transfer device, and take it out! This will finally reveal the DOOMSEYE! Move out!"
General Alex Miles: "That's it! That's the DOOMSEYE... It's gigantic..."
Federation Marine: "General Miles! Our scans show a massive energy surge coming from the DOOMSEYE!"