unbreakable: What evidence is there to suggest that? I say false, you said yourself, Ven's broke.
Ability to cut through EXTREMELY tough material: This one's cool.
Medium of either Light, Darkness or Twilight: Not sure there's a medium of any kind, no real evidence for that.
Can be dual weilded: Well no ****. What, some magical force might prevent someone from holding 2 at once?
Require keychains: Pretty sure BbS's didn't have.
Can lock anything: Debateble.
Can be pretty much any "sword" it wants to: What? Way to the Dawn is not a katana, this point is... what?
Connected to certain realms. (Sora has the light realm key, Riku has Twilight, Mickey has dark): Well Kairi has one, and I don't recall a twilight realm, so unlikely, at least in entirety.
Unlike Leon's gunblade, it can control more than one element: Most of this is arbitrary stuff that doesn't need to be stated for obviousness, you realize.
Transform: That's the keychain I believe. Keychains are supposedly made from memories, which would make sense.
