A misunderstanding. The Shards Yima gave you... Hm. It is not impossible that this would be the case. But it depends on the soul. I meant that if you drew the souls from the tree to Zenith's world, there would be five additional copies of you. As an example, but also theoretically.

As for your question, simple. I have had the time and the skillset needed to survive. The first generation is when I arrived. The time since is difficult to count. But over a thousand years, surely. Perhaps a few. Irrelevant, in a way.