This thread is to collect and crowdsource information about the characters that appear in the game. I'l collate shared information into the OP.

Consultants:

Markku "Mark" Siltanen (main character):
A man who beats people to death with a flashlight in the tunnel. By the time the game starts, he's already seen the darkness and corruption Stalburg has to offer ;P. Mark works for National Consulting Group and appears to be a senior engineer, judging by his cushy window office.

Paul Lauwrens:
Mark's immediate boss and the person he stays in contact with by phone throughout the game. Genuinely concerned about his employees' well-being and the improvement of Stalburg. Puts up with a lot from Mark.

Amit (Rahal?):
One of the other engineers in Mark's department. Assigned to visit the Twin Gorges Dam with Carla. Twin Gorges was reportedly in as terrible condition as Hammer Valley.

Carla (Conagher/Diethart/Västerstrom/Jonhson?):
One of the other engineers in Mark's department. Appears pessimistic/cynical about the likelihood of infra repairs. Assigned to visit the Twin Gorges Dam with Amit. Twin Gorges was reportedly in as terrible condition as Hammer Valley.

Steve (???):
One of the other engineers in Mark's department. Appears directly familiar with Plow Edge River infra, mentioning a prior bridge collapse there. Assigned to Plow Edge River.

Businessmen:

Alex Hartmann:
Former director(?) of Hammer Valley Dam and other infra companies. Believes a wide-ranging conspiracy theory, led by Jeff Walter, was behind the failure of his dam and a variety of other city infrastructure and companies. Alleged as unstable by his ex-secretary, XXX(Kathleen?)

Jeff Walter: The mysterious billionare Walter seems to have started a number of companies in the city of Stalburg and intentionally made a number of them fail, all towards some nefarious end- or so AH believes. Has gone missing recently, along with Xeander Berg.

Eric Kleinmann:

Xeander Berg: An engineer who worked with JW to build the water tunnels that supply Stalberg. Missing?

Mikail Rosenthal:


Explorers:

Hans:

Lukas:

Stalburg Water:

Marko:

Maxim:

Tunnel Maintenance:

Erik: The senior maintenance worker on the tunnel system. One of two left over after the collapse of the Bergmann company. Nearing retirement, apparently injured by his junior partner, Robin, to keep him from leaving.

Robin: Junior maintenance worker on the tunnel system, brought in after the layoffs. Has a reputation as "crazy" and unpredictable- potentially as a side effect of exposure to toxic, glowing green mushrooms in the tunnels. Alleged to have injured Erik to keep him around. May know more about what is going on than meets the eye.

Others:

Max Koller: Police officer charged with investigating disappearance of XXX. Believed to be part of the conspiracy by AH.

JK: Maintained the forgotten power plant. Note suggests he had a heart attack/stroke in early 2003 that severely impaired his mobility/motor functions. After he stopped appearing at the site in late 2003(possibly dying) it appears to have been left unattended.

Hammer Valley Ranger: Alcoholic- trusted by Hartman with his "stash" of funds, which he has dipped into to supply his habit after being laid off.