At this point no one except the author themselves can understand where this story is going to be.... Up until Ranmaru died in the sengoku era, everything made sense, but after he went back to the original world with different timeline, idk I don't think that part is important enough, like, in the end he died again and went back to the sengoku era....
Either it's because Nobunaga meet someone who looks like Ranmaru (who's supposed to be died already), or he went to the timeline where Nobunaga is the ruler and someone calling his name just like that made him think 'who the fuck are you calling my name like that as if you are close to me? Don't you know who I am?'
Well................. hopefully we will get clearer situation in the next chapter...... so see you in 3 months maybe....?
Everyone in the comments talking about alternate timelines but I interpreted the end of the chapter as like. .. he comes back as Mori after he's been presumed dead for a while, so nobunaga thinks he's an imposter or something??? Am I stupid