I am a technical intern in a factory in Japan. I ran away when the factory was repatriated, but my visa was still half a year away.

In Japan, 24 hours after the trainees disappeared, their factories and organizations had to report to the police. Therefore, there is no doubt that your group called the police, otherwise he will be responsible. So, even if your visa is still half a year away, you are still illegal. You are blacklisted. If caught by the relevant authorities, they will be sent back to China.