You will need to make a character and can find more information on how to do so on this page.
Be sure to read that page thoroughly, almost all the info on it is important for making your own ninja.
To join a faction look at your options here before talking to an admin on the subreddit about joining one!
Look at the different clans available to be a member of here - or even make your own! (Be sure to give it it's own page if you do so.) If you're joining an existing clan, check for member limits to see if they are open.
As you role play and your character develops, visit this page for simple instructions on how to improve your character by adding to your stats and gaining new abilities.
Look here to see some other players' characters, and try not to clone them!
Once you have made a character, you can submit them for approval.
One character per player. Inactives can be made at any time, but they cannot be used in game until you choose to switch from an active character to an inactive character. Inactives are not NPCs and remain inactive and "off screen" so long as they are listed as inactives.
Etiquette and fair play are important in role playing! Check out Nafarias' Guide to Roleplaying Etiquette for some guidelines and rules to be aware of.
Our guidelines on earning QP should also be read - this will tell you how to earn QP, which is used to purchase feats that enable your character to learn more abilities and advance through ranks.
NPC rules - You can make an NPC of any level(within reason) with any abilities for your character to fight or interact with. Others can join you in fighting this character. These NPCs can provide useful information about your character's past or background and serve as a means for developing your character. You cannot make NPCs to do any of the following: protect your character, fight against other characters in lieu of your own character doing so, or serve as a tool for providing information relating to other characters. Inactive characters are not NPCs. NPCs of your own making are not autonomous, either, and limited to interactions with your own character.