The Ghost is an NPC that will appear at the beginning of each island, representing the fallen king/queen who came before you. They will try to lead you in the direction of the Kingdom, and will disappear once they make it there with you.
The Vagrants (AKA Beggars) are NPCs who spawn at Vagrant Camps, and are the only way to populate your Kingdom. They will wander around aimlessly within a certain vicinity of a Vagrant Camp, and are completely ignored by Greed. When paid a Coin, they will be hired to work for your kingdom, and thus will turn into a Peasant.
When a Vagrant is given a Coin, it turns into a Peasant, and the Peasant will go to your Kingdom’s center. A Peasant is anyone in the Kingdom who isn’t a Vagrant, and doesn’t have a job. When there are available tools, peasants will pick them up and do the job associated with the tool. During the day, the Peasants will wander near the shops awaiting a job. At night, the Peasants will run back to the center of your Kingdom and wait until morning. If chased by a Greed, they run. If they get hit once, they drop their Coin and become a Vagrant. Peasants can collect a maximum of 2 Coins at a time.
The Archer is the cheapest unit in the kingdom. Peasants can become Archers by picking up bows. During the day, Archers will wander between your outer Walls and the forest, hunting Rabbits and Deer. At night, they run back to and hide behind the outer wall to defend the kingdom. They will run away from Greed, but will occasionally stop to shoot at them. If they are hit once, they drop their bow and become a peasant. Archers can collect a maximum of 10 coins at a time, and have a (1/3?) chance of hitting their target.
The Worker (AKA the Builder or Engineer) is the one who builds, mans heavy weaponry, cuts down trees, and repairs your Kingdom. Peasants can become Workers by picking up hammers. During the day, they wander around the last site they worked on. During the night, they head to the outer Walls and wander around there. They will run away from Greed, and when hit, Workers drop their hammer and turn into a Peasant. Workers can collect a maximum of 2 Coins at a time.
The Farmer is the main money maker of your Kingdom. Peasants can become Farmers by picking up scythes, going to the nearest available Farm, and making a crop field. During the day, they will grow and harvest Coins for you (seems legit). At night, they run back behind the Kingdom’s Walls, or stay at their farm if it is a Tier 2 Farm. They run away from Greed, but are the slowest unit in terms of speed. If a Farmer does not have a valid farm to work at for 5 days, they will drop their scythe in the water and become a Peasant, which will happen en masse once winter starts. When hit once, they drop their scythe and turn into a Peasant. Farmers can collect a maximum of 14 Coins at a time.
The Knight is the best attacker/defender of your Kingdom. After you get a Tier 6 Kingdom, you can buy shields for 6 Coins each, two shields for each side of the Kingdom. When there is an available Peasant, they will go over and pick up the shield to become a Knight. When this happens, 4 random Archers will join the knight’s squad. These archers follow and protect the Knight, and do not hunt animals. They are distinguished by their colored armor. During the day, the Knight guards the border of the Kingdom. At night, he retreats behind and guards the outer Wall. If the Wall is 50% damaged, he retreats to the next outermost Wall. Knights can counter an attack once, but if they get hit again before recovering they drop their shield and become a Peasant. If you give a Knight Coins, it buffs their defense, and they can counter more attacks. You can give them a maximum of 7 Coins. After buying your second Wall, at your outermost Walls you will find a flag post with the option to pay 4 Coins. Doing this commands one of your Knights on that side of the Kingdom to attack the nearest Portal in that direction.
The Banker is a moneymaking NPC, who spawns automatically once you have the “church” built from upgrading to a Tier 4 Kingdom. He has many different looks, depending on what coat of arms you have. He goes inside during the night, making him and all your money that he holds completely safe from Greed. During the day you can give him Coins, which he will collect and store in the bank. He can only carry 10 Coins at a time, while the bank can hold an infinite amount of Coins. For each day that passes, the amount of Coins in the bank increases by 7% (it can never exceed 8 Coins per day, so at 101 Coins your interest stops growing). The interest is rounded up, so you will get at least 1 Coin per day, as long as you have invested at least 3 Coins. Because of this, it is a great idea in the long run to store Coins with the Banker. During the day, if you have more than two Coins in the bank, you can withdraw up to 33.3% (1/3) of your stored Coins by walking by the Banker. He never gives you more than your bag can hold.
On your first day the Merchant will be standing next to your fire, with bags on his donkey. Next morning, he will drop some Coins for you if you walk by, which will remove the bags from his donkey. He will then wait for you to pay him 1 Coin, and if you oblige, he will (if its not already night time) travel out into the forest to the Merchant’s Hut. When he gets there, he will take a few seconds to equip his donkey with some new bags before he heads back to your Kingdom. This process cannot be repeated once you destroy the Merchant’s Hut (by removing the Trees around it), and he will disappear shortly after. The Merchant is only available on islands 1 and 2, and cannot be killed by Greed.
A Hermit spawns from a Hermit Shack, and can be carried with you for 1 Coin, which will enable you to upgrade a Tier 4 Tower into a specific Tier 5 Tower. After upgrading a Tier 4 Tower, traveling past your outer Wall while enemies are present, carrying them for a day, or switching mounts, you will drop your Hermit and need to pay another Coin to pick them up again. Each of the Hermits can be brought with you on a Boat or through a Teleporter, as long as they are with you on your mount. All of the Hermits will stay behind your Walls like other NPCs, but unlike other NPCs, they can be picked up and carried away by Greed like a tool or coin. The type of Tier 5 Tower that you can upgrade Tier 4 Towers into depends on which Hermit you have.
The Hermit of Tide upgrades Tier 4 Towers into Mighty Ballistas.
The Hermit of Valor upgrades Tier 4 Towers into Armories.
The Hermit of Baking upgrades Tier 4 Towers into Bakeries.