If
Kinoko Nasu was the one who wrote the story:
"I will win. I WILL MAKE SURE I WIN," the bro said resolutely.
This is the moment when the bro unleashed his
Noble Phantasm and
Mystic Code, his ultimate form of
Protecc Imouto. It is the "
Sword of Retrograde" and an indefeasible blade of the gods, divinely protected by siscon will, that works by using a conceptual curse to warp destiny and a divine trick that uses time as its blade. It warps causality to always strike the target goal with a concentrated force. The condition for its use is that the opponent must be the imouto, and
Protecc Imouto must be used for the sake of imouto. It would normally be that Protecc Imouto would prevent any harm that would befall the imouto.
In this case, the bro released it to win the Jankenpon match and protect his imouto's heart.
Despite being released afterwards and no matter how fast the imouto show her hand,
Protecc Imouto always strikes a winning hand by changing the flow of time to rewrite events so that it makes the winning hand against imouto's as the opposing hand was ever made in the course of the world. Rather than just rewriting events to stop the imouto from showing her hand, it is severing the fate of the imouto winning, reversing and changing the flow of destiny of both the bro and the imouto should the bro ever pulled a draw or a lose. The bro's not-winning hand, returned to a point where it "
couldn't happen" due to the the bro being affected by
Protecc Imouto, is wiped out by the laws of the world and the absolute system of time. No matter the power or speed of each of their hands, it is impossible from the bro to not win if the bro has all his not-winning hand possibilities voided before he even started showing his hand. It is an ability using bro's siscon soul as bait to counter all of imouto's possible hands that both kills his not-winning hands and protected Imouto's heart, creating a perfect balance between offensive and defensive capabilities to win this Jankenpon match.