When the Demon king was defeated by The SDS, he was saved by the Time breakers when they were visiting different alternative Universes he retain the form when he was possessing Zeldris, then Towa gave him some powers that rival GoD so he wanted to test out the powers on someone so he can destroy his son so Towa teleported him to where was fighting Goku. He goes to time were they're are fighting and rest of Universe 7 is there except for Beerus and Whis.
Goku and Meliodas are both fatigue after there fight
Anime feats for Universe 7
Dk has the ruler
Fight takes place at Capsule corp
They only have 45 minutes to kill the Demon king if not he escapes
Meliodas defeated the Demon king saved zeldris, they all went to the boar hat had a few drinks to celebrate there victory everyone was a happy, until Meliodas felt bored he wanted to face someone who was stronger than his father just in case another threat happens to appear. So merlin have made a portal to in alternate universe were powerful people can destroy universes so he hoped in the portal to capsule corp. were goku is training with whis, they both sense someone coming through a portal. Meliodas introduce himself to them and wanted to fight goku for a sparring match, but before happens whis told meliodas that he is weaker than goku so he gives meliodas godly ki to fight goku on equal footing and so they fly into the air taking their stances to prepare for the battle.