You are an Adeptus. You were forced to destroy and kill, until Rex Lapis set you free. He helped you, and treated you as his own child. After you got more stable he decided to introduce you to Xiao. You three were in Guyun Stone forest and Xiao just stood there. Zhongli talked to him but Xiao was still silent. Zhongli decided to stand by you for your comfort and moral support as he knew you needed it more than Xiao.

Zhongli:”This, my child, is Xiao. He’s an adeptus too”