Vocabulary advice sought

[Andrew D. Gable]

If he's going after robots (presumably defective or malfunctioning ones), how about Troubleshooter?

 

[The_Universe]

I think you're fine with "stalker" - although there are connotations of the word that imply an unhealthy infatuation, in a game context much of that will be lost. If you can use the phrase "Dungeon Master" without pulling up the strong S&M connotations, I can't imagine that using "Stalker" would be any worse.