Each level up you'll unlock more Heroes, Neighbors and Monsters! Once a character’s house is built, you get the new character related to it. Each character has a story to play, he'll give you new quests to complete! Collect every character and play every mission and you'll earn a lot of experience and coins.
Characters appear in the first 3 tabs of the market: Monsters, Heroes and Neighbors. Select the character you want to place:
Place the house and wait it's construction time and you'll unlock a new character:
Character will appear walking in the city with an exclamation mark to play their story: