DragonBall XG

2 years after the distruction of Ultimate Shenron, something happened and all of the enemies defeated by Goku, Gohan, Goten, Vegeta, and Trunks, are back. They are x1000 stronger than when they were defeated. This might be the end for the Z-fighters for ever.

Return of Frieza Saga
Frieza was the first defeated enemy to appear from hell. He will try to get his revenge on everyone who wronged him in the past.

Return of Cell Saga
Cell originally came from hell immediately after Frieza opened the dimensional rip. He stayed in the background while Frieza was fighting Goku. Unlike Frieza, though, Cell wanted Goku to be at his full strength when they fought.

Friezer Saga
After finding all 7 DragonBalls to revieve his brother, Cooler shows Frieza the Fusion Technique. They performed a perfect fusion strong enough to destroy Goku as a SSJ 5.