Sutter was a thief, and a member of Felix's crew who went into the Bonehoard to acquire the Horn of Quintus. He was the last of Felix's companions left during their expedition. After losing Dranko and Marcus and witnessing the gruesome death of Cather, Sutter decided to abandon Felix and escape from the Bonehoard. He nearly made it out, but was too tired to go on. He died in a small out-of-the-way chamber near the exit, either from zombies or exhaustion.
In his journal, Sutter made reference to several matters, including their guide markings (arrows pointing back toward the entrance), the loot carried by Marcus (on Hard and Expert), and the 'X' markings left by some other group (Expert only). Though the specifics are not known, it is clear that he did not like Cather.