So Claire Taylor just gave the worst tip ever. Don't do what she did at all. Do not get a second ninja until your first ninja is a full power level 50 black belt. One full power black belt will beat 10 various belted ninjas easily. One ninja with a lot of power is way stronger than multiple ninjas with spread out power. Do not, I repeat do not buy a second ninja until your first ninja is fully levelled up. You have been warned. A black belt will destroy with no contest let's say a purple belt and a red belt or a brown belt and a red belt or even two brown belts. So make sure you understand how much weaker you are if you buy multiple ninjas and spread out your karma leveling them each up.