My complete theory on the Triforce:

- When it is together and not moving, that means that it is at rest.
- When it is together and the pieces are separated a little and spinning, this means the Triforce is united and active. The Essence of the Triforce is acting.
- When an inbalanced person tries to claim the Triforce, it splits up, and the two other pieces reside "in the hearts" of two others, chosen by destiny. They literally reside inside the person, thus ensuring that the only way the pieces can be taken is if the holders are killed or willingly give the pieces up.
- A holder can willingly make the Triforce piece physical again (if they know how) and even split it up to hide it, as Zelda did in LoZ.
- When a Triforce piece holder is slain, the Triforce piece will become material and pop out of their body. This is what happens in LoZ when you beat Ganon.

My complete theory on Ganon:

- In OoT, Link killed Ganondorf, but he used the Triforce to keep himself from dying completely. He came back as Ganon.
- In ALttP, Link had the Master Sword and the Silver Arrows, so he was able to completely destroy Ganon's body. Ganon's spirit was banished to the "Dark Realm."
- In Oracle, Twinrova used the three flames to bring Ganon's spirit back to Hyrule. They planned to rebuild his body by bringing his spirit into Zelda's body. But Link stopped them, so they brought Ganon's spirit into their own body instead. This had the effect of bring Ganon back as a raging, mindless madman. Link didn't have the Silver Arrows, only the Master Sword, so Ganon's body turned into ashes. Between Oracle and LoZ, somebody revived Ganon's ashes. Or, perhaps Ganon warped away before Link could defeat him. He builds an army and waits until LoZ before striking again.
- In LoZ, Link only had the Silver Arrows, not the Master Sword, so Ganon's body turned to ashes again. Therefore, Ganon is still a threat after AoL, until either Ganon's ashes are destroyed or Link uses the Master Sword and Silver Arrows to completely destroy Ganon's body again.

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The way I see it, Ganon can never be killed for good. In ALttP, his body was completely destroyed. As far as I know, Ganon's spirit was sent to an afterlife of sorts. But it's still possible to bring back Ganon's spirit from this afterlife and reincarnate him.

It's far easier to bring back Ganon's ashes than his spirit, because in this case the reincarnation is already taken care of. Ganon's spirit is in the ashes, and Ganon simply rebuilds his body out of the ashes. Twinrova was the only one who knew how to bring back Ganon's spirit, and the process itself was very difficult. Since Twinrova sacrifices herself in Oracle, it's doubtful that the ceremony could ever again be performed. So, if Ganon's body is ever completely destroyed again (after AoL), it will probably be impossible to bring him back, because Twinrova isn't around to perform the ceremonies.

Consider that, in Oracle, Ganon is brought back by using Twinrova's body, which results in him being mindless and raging. I assume that, in LoZ, he is still mindless and raging, because he is revived out of the same ashes. This is why he isn't as clever and cunning in LoZ as he was in OoT and ALttP.