From iRO Wiki
Ninja Mastery (Alt: Ninpou Training) is an Expanded class passive skill available as Ninja.
Through the Ninja Arts, enables the natural recovery of additional SP every 10 seconds while the character is not moving.
|Base Regen||Rec. Bonus|
- No SP is restored if normal SP regeneration is not permitted (i.e. the user has overweight).
- SP will be replenished as long as the user does not move itself from whatever cell it is located at. This means if they attack or use skills against a monster for twenty seconds while staying on the same cell, some of their SP will be restored twice.