You could be banned for vandalizing, spamming, removing large amounts of content from pages, creating pages unrelated to Reborn!, uploading spoiler images or adding info you got from a spoiler site, and any other action that hurts this wiki more than helps it. You can also be banned for harassing and/or making personal attacks against other users.
Not to worry, every ban can be lifted, so if you think you were wrongly banned or realize your mistake, leave a message on your own talkpage, and an admin will check it and give you another chance, if deserved. (Warning: If you keep repeating the same mistakes, don't expect us to keep being lenient) (Note: Length of the ban varies on the amount of harm done)
If you believe a user should be banned, leave a message on an admin's talk page, along with the reason on why you think the user should be banned. The admin will review it, check the user's edit history, and decide on what to do. Don't request for bans over disagreements or arguments unless the other user starts to make personal attacks.