Jacob Marsh

Jacob Marsh is the son of Sebastian Marsh and a manager of the Marsh Refinery.

Role in the game
"'You fool. You've got no idea what you are dealing with here. I want you to witness the power of the Order of Dagon. I'a! Dagon! I'a! Hydra!'" Jacob is mentioned multiple times through the first half of the game, mainly by Lucas Mackey who even had an appointment with Jacob, but he never showed up.

During Jack’s interrogation in the Asylum, Hoover revealed to him his goals – the capturing of Jacob Marsh and finding the incriminating documents about the Marsh family. This eventually led to the raid on the Refinery. Jacob, in the absence of his father, organised defences and armed the refinery workers. When FBI agents arrived they were met with fierce resistance, and as a result, most of them were killed.

When Jack finally finds Marsh, Jacob will attempt to kill him by throwing him into a grinder. After his failure, he will also try to murder Hoover by drowning him in the molten gold. During the process he will get interrupted by Jack, who will shoot him, thus seriously wounding him.

With his men in disarray and himself wounded he will try to flee the Refinery, but not before trying to once again kill Jack, this time by unleashing the Shoggoth. He will fail again and will get arrested by Hoover alongside Agent Harper. After that he is taken away, most likely to a prison, but his final fate is unknown.

Personality
"'The Order of Dagon will make you pay for this Hoover. I'a Cthulhu! I'a Dagon!'" Jacob seems to be fully indoctrinated into Order’s beliefs, often making references to the Order and chanting “I’a Dagon!” and similar mantra. Due to his family he is definitely one of the more influential people in the town. His position of the Refinery manager also gave him great influence and respect.

Trivia

 * Jacob seems to be the only shown member of the Marsh family who survives the events of the game.
 * His ugliness is referenced multiple times throughout the game (also his face is barely shown or very hard to see).