You gain your own Ninja Mask and NinjaNomicon, when worn, the mask will turn into a ninja suit that gives you superhuman physicality, a hammerspace that stores items like weapons and smoke bombs, Resistance to magic as well as enabling the use of magic ninja skills.
Your NinjaNomicon is an ancient book that puts you into a trance and takes your mind inside the book to grant you wisdom and/or skills depending on your needs, the skills are both mundane and of magic abilities of the ninja, the book is precognitive in nature so it knows what to teach every time it's opened but you can choose to go to a specific lesson if you're determined enough.
If you have good enough character then you will not go mad if you don't mind-wipe yourself using the ultimate lesson for more than 4 years but you can still choose to do it, removing your memories, wisdom and skills as a ninja, integrating them into the Nomicon and making the enhanced abilities pass into a new suitable ninja.