I am building a game and taking some inspiration from both Torchlight as well as Orcs Must Die. It would be a Tower Defense type game. The basic player mechanics would be similar to that of Torchlight, where the camera is mostly top down and target enemies using mouse clicks, being able to do simple attacks as well as cast abilities. Then there is the trap building mechanic, where the player is able to build traps around the level in order to kill the enemies to prevent them from reaching the end goal. My problem though, is that I am not very good at coming up with story ideas. Or a motivation for the character. At first I was thinking about introducing Elements to the game (Water, Fire, Earth and Air) but I am unsure about this idea, and still don't know how to make a story out of it. If anyone has a simple story idea or motivation for my main character to be building traps and shooting stuff, I would be greatly appreciated.