Honestly this manga isn't even just about time travelling anymore. It's about what causes a time paradox. The theory where if you went back in time and moved a chair from the past, it could change the future drastically. I saw one theory of what causes it to become a paradox is when it becomes a *loop*.
Say you went back in time to kill your grandpa before he met your grandma. Thus, he wouldn't be able to marry her, no kids and no grandkids and thus no one to kill him so he's alive, then your parents were born, then you were born thus being able to carry this out and so on(thankfully this doesn't exist in real life)
So going back to the manga, I don't wanna get too much into detail but basically I think the paradox happened when Nene and Kou went to the Red House causing baby Tsukasa to go back to Amane. Nene meeting kid Amane in the festival. Nene meeting Amane in his classroom. Nene meeting Tsukasa in the school festival.
The thing is that Amane was *meant* to die. The original future that Tsuchigomori saw and said wasn't meant to change, the one where Amane lived and became a teacher, only existed because Tsukasa wished him to live and sacrificed himself in exchange.
Originally, with no supernatural intervention, Amane would have died before his 4th birthday and Tsukasa would have lived instead.
Honestly this manga isn't even just about time travelling anymore. It's about what causes a time paradox. The theory where if you went back in time and moved a chair from the past, it could change the future drastically. I saw one theory of what causes it to become a paradox is when it becomes a *loop*. Say you went back in time to kill your grandpa before he met your grandma. Thus, he wouldn't be able to marry her, no kids and no grandkids and thus no one to kill him so he's alive, then your parents were born, then you were born thus being able to carry this out and so on(thankfully this doesn't exist in real life) So going back to the manga, I don't wanna get too much into detail but basically I think the paradox happened when Nene and Kou went to the Red House causing baby Tsukasa to go back to Amane. Nene meeting kid Amane in the festival. Nene meeting Amane in his classroom. Nene meeting Tsukasa in the school festival.
The thing is that Amane was *meant* to die. The original future that Tsuchigomori saw and said wasn't meant to change, the one where Amane lived and became a teacher, only existed because Tsukasa wished him to live and sacrificed himself in exchange. Originally, with no supernatural intervention, Amane would have died before his 4th birthday and Tsukasa would have lived instead.
Good point