Meet Jackson David Matthew Stevenson, known mainly as JD or Jack. He's 36 and another one of those nice guards on the island and often seen patrolling alongside his BFF and fellow guard - Ian Marsh. He works alongside Ian with the food distribution and also the secret smuggling ring, while his friend usually sneaks in goods and things JD runs an underground postal service - he's got a private mail box in an assumed name on the mainland and is able to send and receive letters and small parcels from those on the island to their families.
Although he looks like he could crush your skull with his impressive arms he'd be more likely to crush you in a bear hug, he's an overall nice guy and follows orders like a good soldier - to a degree. JD won't harass the residents on the island even if his superiors tell him to, but he's not going to just sit back and take any kind of abuse from residents or fellow guards.
His bio is here with some of his history. Any lines are welcome, residents he's nice to or those who he's smuggling letters for.