Players will receive first time bonus when they play multi-player mode with new partners.
Ninja Pearl is obtained as first time bonus and it is stocked within present box.
Limit to first time bonus
Player will receive first time bonus up to a hundred times. There is no bonus for completing missions with a new player after that.
How many Ninja Pearl can be obtained?
The total amount of Ninja Pearl obtained as first time bonus is 110. 2 Ninja Pearls are given by each time until 10th first time bonus. From 11th, players gets a Ninja Perl each time.
I feel that for the free to play players its nice to have this but its also unfair to limit it. I don't spend money on the game and the people who do are going to be that much better its very annoying. if we were to still gain pearls I think I would play the game more often because right now its just boring. There is no new campaign missions or anything on global so I can't get more pearls. What you should do is you should renew the 110 pearls every new update for us free to play players.
Not sure but usually it can be because you already have reached the limit of what you can earn from multiplayer but you can still earn ninja pearls from finishing the mission quests like Heart elements only etc. or earn 1 pearl for getting all the drops on a certain stage including the lucky drop. Hope this helped :)