They are not exact mirror images. Some of the races that appear on the Shards are the same that you find on the Source. As far as history and culture go, they are completely different. Time between Shards vary, so what might be mere months on the Source may be many, many years on another Shard.

Some on the First are now aware of the existence of the Source. The same goes with individuals from the Thirteenth. In general, it is not common knowledge.

Then as far as the person who is ultimately responsible... My friend defeated her and then reached out in friendship.