The Vinsmoke family is a powerful and infamous murder family in the New World.  Also, they are the current royal family of the Germa Kingdom, former conquerors and rulers of the North Blue.  In addition to their government over the kingdom of Germa, they are the commanders of the realm that is located in the New World - Germa 66.
Ichiji is a serious older brother with red hair, Niji is arrogant and likes to flirt with girls, Niji has blue hair, and Yonji is quiet but aggressive with green hair 

Ichiji's eldest, then Niji, and after Yonji 

Ichiji is the second child of the king and a captain in the army of Germa 66. He is proud of his royal heritage and considers himself superior to the commoners.  Ichiji shows coldness and cruelty, unable to sympathize.  He puts tasks above the lives of others, even his own subordinates, and shows no pity for those killed in battle.  Ichiji is more violent and calm than his younger brothers Niji and Yonji, but can become violent and cruel if provoked.