Question: how to unlock all characters in jump ultimate stars?
Answer: Allen ... Unlock when you collect more stars than your opponent before the time runs out on the D.gray.man first mission.
Don patch ... Avoid being hit for at least 2 minutes in the 2 mission of bo-bobo.
Gohan ... ... 
Gon ... ... 
Hitsugaya ... ... 
Ichigo ... ... 
Kakashi ... ... 
Kazuki ...