Ends of the Earth
The Ends of the Earth is a Keychain for Terra's Keyblade that is found in Kingdom Hearts II Final Mix, Kingdom Hearts Birth by Sleep, and Kingdom Hearts III. Like Terra's other Keyblades, it can Formchange into multiple forms, including a whip, a spinning-cog weapon and a much-larger Keyblade. Terra also uses this Keychain in order to form his Keyblade Glider and Ultima Cannon.
Kingdom Hearts Birth by Sleep
Terra's Keyblade develops this form after he chooses Riku to inherit the Keyblade. Terra's Keyblade takes this form once his body is stolen by Master Xehanort and his armor becomes the Lingering Will, although it temporarily returns to its Earthshaker form in order to rescue Aqua in the Realm of Darkness.
Kingdom Hearts II
The Ends of the Earth returns to the Lingering Will and remains with it, up until the Will is met by and attacks Sora.
Kingdom Hearts III
After Terra retakes control of his body, the Lingering Will and its Ends of the Earth disappear[?], and Terra uses the Earthshaker Keychain instead.
Being an upgraded version of the Earthshaker, the Ends of the Earth features a longer and more extravagant blade with teeth on both sides at the tip of the blade. The hand guard also elongates to form a wing-like shape of sorts. The Keychain is a rock fragment similar to the one on the Earthshaker. In Kingdom Hearts II Final Mix, it doesn't have a Keychain, as the Keychain had not been designed by the time that Kingdom Hearts II Final Mix was released. In Kingdom Hearts Birth by Sleep, the blade's length appears to be slightly smaller, and the teeth of the blade aren't quite as wide as the Kingdom Hearts II Final Mix version.
The Lingering Will can Formchange the Ends of the Earth into a variety of weapons, including a drill-like object for the forward thrust that serves as the combo finisher, a whip that deals less damage than its blade form in exchange for greater speed and range, a Keyblade Glider, a cog-like object, and Terra's Ultima Cannon Shotlock. Unlike when Terra's Shotlock is used, however, the resulting blast can be deflected via a well-timed Guard to damage the Lingering Will instead. This leaves it vulnerable to further attacks.
"Ends" can refer to the death or result of something, while "earth" refers to the Latin meaning of Terra's own name. "Bane" is a source of misery. Gaia is a deity in Greek mythology representing the Earth and the mother of the Titans. Her Roman equivalent was named "Terra" or "Tellus". "Gaia" is also a recurring term in the Final Fantasy series. The term "Ends of the Earth" is also a common colloquialism for extreme effort or will, possibly symbolizing the powerful will that Terra possesses.