Oblivion (Keyblade)

In Kingdom Hearts 358/2 Days, it appears as a weapon for Riku, and 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 absorbing Xion (Kingdom Hearts). Fundamentally, the Oblivion is symbolic of Sora's memories of Riku.