When this card is flipped face-up: You can Special Summon any number of "Ninja" monsters, except "Senior Silver Ninja", from your hand and/or Graveyard in face-down Defense Position. There can only be 1 face-up "Senior Silver Ninja" on the field.
How to Get
Special Summons from your hand / Special Summons from your Graveyard
This guy is very powerful, the problem is sending enough Ninjas to graveyard for this to work. However, if you get his effect you can swarm the field with 2 extra ninjas, better if it's 2 Red Dragon Ninja to remove 2 cards when they get flip summoned.