[HP fan original work + Sirius is reborn + all members survive]
Sirius was hit by Bella's spell and fell into the curtain of the Department of Mysteries. He looked at Harry Potter's face ashen and saw Lupine stiff, but he could not wait until James came to pick him up and go to another world. He was reborn.
After rebirth, Sirius had mixed feelings and was determined to protect James, but Regulus was curious about Sirius' changes.
Purpose: To save the regrets of those generations.