King Boo

King Boo is one of Bowser's assistants in The End of Mario.

Original Appearance
King Boo is most famous for his appearance in Luigi's Mansion. He also appears in Super Mario Sunshine, Super Mario 64, Mario Kart: Double Dash!!, Mario Kart Wii, Mario Baseball series, Super Princess Peach, Mario Party 8 and Mario and Sonic at the Olympic Winter Games.

Leadership
Not all Boos call King Boo their Leader, some work directly for Bowser. This means at one point their was a civil war of Boos V.S Koopas. This War was decades ago. The war was ended when King Boo negotiated with King Bowser. He offered a trade, he would give Bowser full control of part of his army if Bowser left him alone. Bowser agreed but some boos weren't happy about this and became rouge boos.

The End Of Mario
In The End Of Mario, towards the End he appears on Bowser's Side. He finds three Mega Mushrooms for King Bowser which pleases him deeply. When he activates the Mega Mushroom he turns into Lord Boo, his most powerful state. Although not as big or powerful as Giga Bowser, he is still invincible to most attacks. At the very end of part one he is killed by Wario.