Origin
Arrancar are the creations of Aizen Sousuke, a former captain of the Gotei 13. Using the Hougyoku, Aizen has gone to Hueco Mundo, the home world of Hollows, and begun using it to give Shinigami powers to Hollows. These Arrancar are not 50/50, but are considered to be about 60% Hollow, 40% Shinigami.
Character Shikai's
Grimmjows-Melee,Using Vicious Claws (After Activating Shikai,You look like u have armor on and when u use attack it looks like claws coming out)
Gantenbainne Mosqueda-Melee,You are Dragon (After Activating Shikai,You look like a dragon with a long tail orange and white)
Luppi-Long Range (After Activating Shikai, when you use the attack button hits two extra tiles)