How did rust lake Rose give birth to Laura?

1, rust lake tells that a living lake needs to absorb beautiful memories (white squares) to keep breathing, while dark memories (black squares) will lead to sudden changes in the weather in rust lake.

2. An article in Paradise Island in rust lake clearly tells that in 1933, Leonard and Frank died through sacrifice, and the alchemist's brother was resurrected as Laura (that is, the woman who escaped from the Rubik's Cube) and became Rose's daughter.