Poison City

A character concept for a story I came up with. In it, mankind colonized a planet rich with natural resources but teeming with monsters. The planet also spews a dense, poisonous fog from its surface. To combat this they built cities high into the air and constructed a sturdy defensive wall made with the materials obtained from expeditions.

Over time though distinctions between "upper city" and "lower city" citizens began to divide the people, the upper levels generally enjoying cleaner air and safety than the overpopulated lower levels. Upper level residents mainly consist of high ranking officials and such, a large majority of whom are cybernetically enhanced.

This particular character is a cyborg enforcer within the main colony, who sympathizes with the lower level residents and often goes beyond the wall on expeditions for resources. Other guy is just a grunt.