Question

when kisaki died in the past timeline that meant there was no way naoto couldve been killed since he was killed by kisaki in the future, if that makes sense

sorry i just realized u were talking about something else—
naoto dedicated his life to becoming a police officer after takemichi told him about the future, so then thats why he wasnt there with hina when she got killed

But the thing is... The moment Takemichi leaped to the future was when Naoto saved him from falling. How Naoto was there when Takemichi hasn't still leaped to the future and takled to Naoto about the incidents? I hope I was clear.

If you're talking about the First chapter, as i remember, naoto wasn't there when takemicchi was pushed. After he fall in the trail, there was this sudden bright light obviously because a train is 'bout to hit him, but after a while the light faded and he gained consciousness when he was back in the past 15 years ago, inside a train. Now this might be confusing but didn't takemicchi went to the Tachibana's apartment to meet hinata, and where he also meet Naoto when he was going home. Naoto was being bullied so Takemicchi helped him. Out of the blue he decided to tell Naoto everything including his sister's death. In the other episodes naoto once said that he only believe it because he was into that sort of thing that time. Takemicchi and naoto then made a pact and join forces to prevent Hinata from dying in the future.

(●'◡'●) i just realized you weren't talking about the first time takemicchi fall in the trail. The answer is maybe naoto knew because he was investigating about toman because they have connections and they are purely the reason why hinata kept on dying.

Yeah I was talking about the first time. Sorry but I don't understand yet, because we know that the trigger that sends Takemichi to the future and past, is Naoto's hand. Naoto wasn't supposed to be there. I think it's just a mistake the writer has made.

I'm still confused ...