Purple Heart Stone

Bai Tianxi, if the sacrifice of one person can save this world, then why me? Liu Changan, Yun Chen, Chai Dayong, Lan Qingyu, and Hua Zhuozhuo all asked us to save the world in one sentence, but in the end they told us that we must sacrifice an innocent life to save the world. So what exactly have we been protecting all this time?