Dragon Ball V is a series that takes place after Dragon Ball GT. It takes place in an alternate timeline to the end of Dragon Ball GT and starts three years afterwards.
Summary: It has been five years since Dragon Ball GT. Goku and the Dragon Balls are gone leaving Vegeta to be the leader of the Z Fighters. Gohan now acts as a committed member of the Z Fighters, trying to follow in his father's footsteps.
Meanwhile Piccolo is still in Hell after the events of Dragon Ball GT and tries to maintain the peace. Meanwhile a secret cult of worshippers of King Piccolo manage to come into contact with their old master and he puts together a plan. Piccolo eventually senses a disturbance and goes after it to find his old self King Piccolo who makes him an offer to fuse together to become an even more powerful being. Piccolo refuses and prepares to attack King Piccolo confident that will all of the power he has gained over the years that he wouldn't be a challenge. He manages to best both him and his men until King Piccolo reveals that his followers on Earth have captured Gohan's daughter Pan, and that she will be killed unless Piccolo went through with the fusion. Piccolo agreed reminding himself that no matter how powerful his dark counterpart became he would still be trapped in hell, and thus King Piccolo absorbs him and becomes the immensely powerful Emperor Piccolo. But Piccolo did not know that once fused, Emperor Piccolo would hatch a plan to merge both Hell and Earth together and rule it as his dominion.