Well, for one thing, when SOMEONE digs a treasure and hits a trap, they can appear.
Not sure if they appear outside of that so...

Whenever you go treasure hunting, which you can do by obtaining treasure maps, which you can get in black market or wanted missions, there's a low chance that win you dig up the treasure, you'll get a message stating that you just released sealed ninja, and it'll be announced throughout the server as they spawn random ninja teams (water main with bloodthirsty chojuro, earth main, lightning with Susano'o sasuke, Deidara with a lot of clay. etc) across various maps, they can then be fought and will disappear, and give your team a reward, which you can receive 2 daily.

Hope that helped....

How good is the reward though?

The best rewards i got so far was a seal scroll. But you can get other stuff like coins, summoning scrolls, stamina pots, etc.

- Seal scroll
- Summon Scroll
- 50 Stamina
- 200k coins
- 100 coins
- Magatama