Legend has it that when God created mankind, he said: No matter what you do, you must pay the same price.
Therefore, the price for the people of V Academy to develop the seventh sense is to become smaller; the price for the Black Moon Iron Cavalry is that there are no other descendants except a few of them; the price for being resurrected by Dr. Amy is to lose part of their memory. But since the resurrection of the dead is an act of defiance, the price is naturally higher: losing the memory of all important people...