This time I will stick to my silly and sweet route and never waver~
Please add some settings, I'm afraid everyone will get confused.
The Sun family guards a forbidden place, and a kind of divine power is enshrined in the forbidden place. A is willing to dedicate his life to divine power and asks for a golden finger for B to use. This divine power will turn into a copper key. After the sacrifice is completed, the divine power is transferred from the copper key to B. B is reborn and A dies, but the soul will remain in the world, waiting for the wish to be fulfilled. Only the sacrificer himself (ghost) can take back the divine power of B and transfer it to the copper key again.
Because the person who stole the divine power was ready to sacrifice his life, the original divine power was turned into a copper key. However, because the sacrifice was interrupted, the first copper key turned into multiple copper keys. There are nine copper keys in the nine worlds, all split from the same original divine power. Due to the strength of the divine power, the golden fingers have different durability. Some will be scrapped after a few uses, while others can be used continuously.
Conception: