Oblivion

The Oblivion is a Keychain for Sora's Keyblade introduced in . In Kingdom Hearts 358/2 Days, it can be upgraded to the Oblivion+. It also appears as half of Roxas's dual set of Keyblades alongside the Oathkeeper, and was transformed from the second Kingdom Key Roxas obtained after Xion returned to Sora. The Oblivion is symbolic of Sora's memories of Riku.

Development
Originally, the Oblivion was planned to be given to Sora by Riku, similar to how Kairi gives Sora the Oathkeeper. As such, the Keychain is a black version of Sora's crown necklace.

Design
Oblivion is similar in shape to the Kingdom Key, though is black and has a longer reach. The hilt guard is comprised of two bat-like wings extending downward. The teeth are in the shape of the Kanji for "darkness" (闇). The Keychain's token is a black version of Sora's crown icon. Like the Oathkeeper, the Oblivion's blade is hollow, but it has a chain passing through the gap. The diamond in its hilt also resembles the diamond in the original logo of Hollow Bastion.

In Kingdom Hearts III, the portion of the blade with the chain is now visibly hollow, allowing see-through gaps in the chain. The handguard is now wider with the wing design pushed further up. The tip of the blade where the chain ends now has the grey portion less intricately designed.

When the Oblivion is summoned in Kingdom Hearts II, black smoke and violet sparks surround it. In Kingdom Hearts III, it starts out as a dark cloud in-hand and the Keyblade "stretches" out in crackling dark energy.

The Keyblade's name means a "state of forgetting or having forgotten", and its Japanese name has the same basic meaning. The Oblivion is often associated with the memories that are passing away, such as when Sora reaches the last floors of Castle Oblivion, or when Roxas begins forgetting Xion following her destruction.

In Kingdom Hearts Re:coded, the names of the Oblivion's upgrades allude to the protagonists of the series: Ventus for "Wind", Riku and Terra for "Earth", Kairi and Aqua for "Sea", and Sora for "Sky".

Gameplay
Riku is the only one able to wield the Oblivion Keyblade on its own in Kingdom Hearts 358/2 Days, though Roxas can wield it in conjunction with Oathkeeper. Riku can equip the Oblivion by equipping the Pandora's Gear or the Pandora's Gear+. The ground combo begins with a forward rush, prompting a -Combo, then a 360° spinning slash on the left side, and finishes with an upward slash with a slight jump. The -Combo has Riku do an uppercut into the air and jump slightly, and pressing again has him do a violent downward thrust. The aerial combo consists of a diagonal upward slash from the right leg, the same slash from the left leg, another slash from the right leg, a smack with the teeth area, and a violent downward thrust with the top of the Keyblade.

Kingdom Hearts 3D: Dream Drop Distance
In the intro of Kingdom Hearts 3D: Dream Drop Distance, Roxas is shown dual wielding the Oathkeeper and Oblivion against Axel; Riku also wields the Oblivion against Xemnas, while Sora uses the Oathkeeper. Later, when Mickey summons Ventus, Aqua, Terra, and Roxas to aid him, Sora, and Riku in a battle against Xehanort, Roxas can be seen summoning the Kingdom Key before it quickly transforms into the Oblivion.

Play Arts Figures
A limited edition Oblivion was released with four other Keyblades in a special Play Arts Figures accessory set, Play Arts Arms.

Final Fantasy Record Keeper
The Oblivion appears as a 6★ Keyblade. It can be acquired from the Relic Draw during the Kingdom Hearts collaboration event. The Oblivion bestows the Arcane Overstrike Soul Break Aura of Darkness when equipped to Riku.