Story Mode
➥ Story Mode is the main story in Ninja Must Die which tells the story of Ninja's battle with the Samurai. Story Mode is the first thing that you will unlock after starting the game, but you need to reach a certain Ninja Rank to unlock the respective Chapter.
➥ There are 3 types of Story Mode: Normal Stage, Elite Stage, and Sidestory Stage. You can change between all of them from the icon at the top right corner.
Normal Stage
➥ The Normal Stage is the default difficulty and you will unlock Story Chapter 1 after starting the game. After that, you need to climb up the Ninja Rank to further unlock the next story chapter. Following are the ranks you need to achieve and what chapters it unlocks:
✦ Rookie: Unlock Story Chapter 1
✦ Junior Ninja: Unlock Story Chapter 2
✦ Senior Ninja: Unlock Story Chapter 3
✦ Senior Ninja (3-Star): Unlock Story Chapter 4
✦ Eminent Ninja: Unlock Story Chapter 5
✦ Super Ninja: Unlock Story Chapter 6
✦ Super Ninja (3-Star): Unlock Story Chapter 7
Elite Stage
➥ Elite Stage is obviously the 'hard mode' in Ninja Must Die, and similar to the Normal Stage, you need to reach a certain Ninja Rank to unlock each chapter in Elite Stage.
✦ Elite Ninja (1-Star): Unlock Elite Stage Chapter 1
✦ Elite Ninja (2-Star): Unlock Elite Stage Chapter 2
✦ Eminent Ninja (2-Star): Unlock Elite Stage Chapter 3
✦ Super Ninja (2-Star): Unlock Elite Stage Chapter 4
✦ Shadow Ninja: Unlock Elite Stage Chapter 5
✦ Shadow Ninja (1-Star): Unlock Elite Stage Chapter 6
✦ Shadow Ninja (3-Star): Unlock Elite Stage Chapter 7
Sidestory Stage
➥ Last but not least is the Sidestory Stage. Currently, there is only one for Pepper (the latest character) and there are no stories for old Ninjas like Kuro, Riki, Souga, and Rin (Maybe there are but in future updates).
➥ To unlock the Choice of Fire Sidestory Stage, you need to obtain Pepper from the time-limited Wish. Each stage in the Sidestory is a battle mode and you're going to use Pepper to complete the stage.
➥ Unlike the Normal and Elite Stages, the rewards you get after accumulating stars are not Jade but Stones instead. Since Pepper is from the Fire element, you will get Fire Stones as rewards.