You can't yet, but they have been dropping heavy hints about it, and you may be able to soon.
You just have to win alot of games and beat Sensei in the Sensei games and then... poof! You become a Club Penguin Ninja! I love being a ninja.
you have to be a member on club penguin to be invisible you have to pay if you have to be a member?
you should become a fire ninja
You become a ninja.
You can't yet.
Go in the ninja hideout, and buy it from the ninja catalog.
Wait there might be in 2012 snow ninja
you cant become sensei but you can be a ninja
1
You can't yet.
No, not really. You can become a master ninja on club penguin, but not a Sensei.
You can become a ninja faster by earning the belts and fighting people more.
it is: ninja there is no code to becoming a ninja on Club Penguin.