#13, #14 and #15 are on a mission to kill Gokou, an order from Dr Gero. #13 is the leader of the group, he is the fastest, most powerful and the most intelligent of all. #13 is programmed so he knows everything about Gokou, every single movement, also Gokou's fighting technique and tactics too. He is also programmed to kill who ever gets in their way, where Trunks, Vegeta, Gohan and Krillin are then involved too.