Human species who hasn’t received any modification, or their descendent. Since they are no longer able to survive on this planet, it is said that they are on the verge of extinction.
In order for humans to live outside, they need support from medication or machines. They can’t directly inhale the air, nor can they eat the food made in the factory because they raise the physical ability too much that they become poisonous.
They are rare, but have no value.

Angel Voice: Notes.