Xie An and Xie Quan are not two brothers. They have the same surname simply because Xie Quan lost a bet.
The two were sent by the underworld to work in the human world.
Xiaohei, do you still remember the past?
I really don't want to see the sea of flowers on the other side.
"Just wait, just wait, I'll be here soon..."
This time, I will definitely guard you.
When you come out, I will protect you until I perish, and you come out, okay...