The origins of the iconic Keyblade weapons have been a topic of discussion leading up to Kingdom Hearts 4. While it's known that Keyblades are forged from hearts that have separated from their bodies, the mystery of protagonist Sora's Kingdom Key remains unexplored in the series. As the franchise has extended over two decades, fans have created their own theories in anticipation of the upcoming game. While some theories connect the Kingdom Key to Sora and the new antagonist, they may not provide a complete explanation from the first title.
Sora's Fatherly Protector
Some fans speculate that the Kingdom Key may actually be Sora's father, a character who has never been seen or heard of in the series. While he has been mentioned before as the one who brought Sora and Riku to Destiny Islands, his physical appearance has yet to be revealed. The heart of the Kingdom Key fits the criteria of being present on Destiny Islands when the Keyblade first appeared, and having a vested interest in protecting his son. However, inconsistencies arise as the idea of protecting Sora clashes with the fact that the Kingdom Key leaves his hands and falls under Riku's control in the first Kingdom Hearts. Additionally, Sora has returned home multiple times throughout the series without ever mentioning his father's absence.
The Master of Masters Travels Through Time
One theory suggests that the Kingdom Key originated from the Master of Masters himself, as his heart travels forward in time without his body and becomes Sora's Keyblade. With the Master of Masters expected to be revealed as the main villain in Kingdom Hearts 4, this idea could unify the different eras of the series. It also raises the possibility of the Keyblade leaving Sora's control as the heart that it is made from becomes the next antagonist. This theory combines two fan theories, including the idea that the Master of Masters is Sora's father, though the flaws with that theory still apply. From a narrative perspective, this explanation offers an interesting explanation for the Master of Masters' presence in Kingdom Hearts 4 and another opportunity for Sora to temporarily lose his powers in the finale.
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