The top 20 Club Penguin characters
Number Twenty: Average Ninja
To become an average Ninja, go to the Dojo and play Card-Jitsu multiple times to earn your belts.  Once you have your black belt, challenge sensei and win to earn your Ninja Mask.  You will also win access to the Ninja Hideout, where you can visit the Flying Flippers Emporium to buy your Ninja Invisibility Costume, Cloud Wave Bracers, and Goldsmith Apron.  Your Ninja Costume makes you officially a Ninja, then you can use your Goldsmith Apron to build your amulet out of gold and a mysterious black gem.  After that, use the cloud wave bracers to create heat for access to the fire Dojo, where you work your way up to be a Fire Ninja and collect to Fire Jewel to put in your amulet.  After that, move on to the Water Dojo, then the Snow Dojo, and then, last if all... The ultra secret Shadow Dojo.

Number Nineteen: Snow Ninja
After becoming an Average Ninja, Fire Ninja, and Water Ninja, you move on to become a Snow Ninja.  Snow Card-Jitsu is rather different from the other Card-Jitsu games, as it is the only one when rather than battle another penguin or penguins, you work WITH them.  You need one Fire Ninja, one Water Ninja and one Snow Ninja to battle three different types of living snowmen.  After completing a certain amount of Snow games, you can enter Tusk's Cave to battle Sensei's old enemy, a mammoth named Tusk.  This is very hard, so usually Sensei will join to help in this final level.

Number Eighteen: Fire Ninja
I can't remember how to play Card-Jitsu Fire, but what I do know is that it's coming to Club Penguin Rewritten soon!!!!!  Club Penguin Rewritten is basically Club Penguin brought back!  Get to it via www.cprewritten.net.

Number Seventeen: Tusk
Tusk is Sensei's old enemy, but he used to be his friend.  I don't remember the whole story.

Number Sixteen: Yarr
Yarr is Captain Rockhopper's Puffle, and was one of the first red Puffle introduced, as the only reason Red Puffles ended up on the island is because Rockhopper brought them over from Rockhopper Island.

Number Fifteen: Herbert P Bear

Oh forget it.  Here's just a list instead:

1. DJ Cadence 🎧
2. Rookie 🐓
3. Jet Pack Guy ✈
4. Sensei 💓
5. Rockhopper 🗿
6. Dot ⚪
7. PH 🍜
8. Rory 🆎
9. Gary the Gadget Guy 🎦
10. Klutzy ♋
11. Aunt Arctic 🎯
12. Ultimate Protobot 3000 ✨
13. Penguin Band 🐧
14. DJ Maxx 🎧
15. Herbert P. Bear ‼
16. Yarr 🎆
17. Tusk 🍗
18. Fire Ninja 🎇
19. Snow Ninja ⛄
20. Average Ninja 🐢
Honourable mentions:
Water Ninja ⛲
Olly ☎
Kat 🈁
Rainbow Puffle 🌈
Gold Puffle 🌟
Pizza Parlour Owner (Ceaser) 🍕
Coffee Shop Owner ☕
DJ Penguin 🎧
Dancing Penguin 🐜
Black Puffle ✴
Secret Agent ㊙
PH Look-alike 🍜
Test Bot 🍶
Wheelbot ♿