Steven Universe meets The Seven Deadly Sins

Adventure time

Peaceful.

That's how things were these days.

And Steven couldn't be happier.

He was riding through town on Lion, and people paid no mind. There was the occasional complaint but that was all.

He could see humans and gems alike taking, walking, laughing together. Getting along. Living in harmony.

People surprisingly accepted Gems with little protest. And humans and gems have been living happily together. There have even been some human and gem couples forming. Steven wondered what it would be like to have other hybrids like him around.

"Hey buddy, wanna go to the park?" Steven asked his pink companion. Lion roared in approval and sped towards the city park. Steven laughed. He truly loved Lion. He more than a pet, he's family.

                                     ***
They spent the majority of the day at the park. Steven was just relaxing on the bench, scrolling on his phone. While Lion was chasing a butterfly.

Suddenly Lion stopped chasing the insect and sniffed the air. He then started sniffing the ground, as if he was looking for something.

Steven noticed this and put his phone away. "Hey, what's up Lion?" He asked. Lion continued sniff around until he stopped. His eyes flashed for a moment, then he started running.

"Woah! Hey wait up!" Steven ran after him. What had gotten into him? The more they ran, the less people he saw. It seemed that they were running towards a secluded area. "Where are you going?!"

Lion kept running. Steven groaned and decided to use his super speed run up to him and hop on his back. That way he could at least see where they were going. Lion paid him no mind and kept running.

                                    ***
Lion had finally stopped. They were in a secluded area hidden by trees and vines. It looked more like a forest than a park. Steven looked around in awe. He had never seen anything like this. In front of them was a huge door with symbols he had never seen before. Steven got off Lion and took a closer look. The writing appeared to be in a different language. It didn't look like human or gem writing.

He also felt a foreign sensation coming from the door. Actually, he felt it coming from the general area they were in right now. He concluded that Lion had also felt it from afar.

"What is this...?" He touched the door, then suddenly the symbols and the words started to glow. Steven stepped back as the door opened.

Inside, it was dark, that is until the room lit up magically by itself. The walls seemed to be in good shape, but the plants had grown over the walls, so it was definitely old. The room had a foreign, yet somewhat serine aura. Powerful too. There were two old yet beautiful fountains on each side. Along with two statues. The one on the left seemed to be a demon, and the other was what Steven guessed to be a goddess.

There were slabs on the bottom of the fountains, they read "The Demon King" and "The Supreme Deity".

"Are these guys gods or something?" Steven asked Lion, even though he knew he wouldn't give him a verbal answer. The feline simply growled in response.

Steven finally turned his attention to the center of the room. He gasped. There was a device resembling a warp pad in the center. It was more of a purplish color however. And there was a stand, with the same foreign language on the door, in front of it.

Steven walked to it and looked at the writing. He touched the words carved into the stone and then they glowed. This time however, the writing translated to English. 'Cool I can read it now'

"This is a gateway created by yours truly. Belialuin. Not just any gateway, one between our worlds. Ever since I discovered the existence of other worlds i just had to see it for myself. I have a thirst for knowledge you see, like my dear daughter. The privilege to explore and study other worlds was just too good to resist. And too make sure it doesn't fall into the wrong hands, I've cast a seal that will only let those with good intentions pass. To those who are reading this, I hope you enjoy the gift I have created~."

Steven couldn't believe it. A gateway between worlds? His life just kept getting weirder! "Lion! Are you seeing this?! This thing can't take us to another universe!" Steven exclaimed, as he turned to faced Lion, waving his hands in the air. The feline, who had been standing beside Steven as he read, titled his head.

"I know! I can't believe it either!" Steven said. He looked around the room again and then at the warp pad. 'Should I go? It might be dangerous. But it's not like I haven't faced danger before. Plus, everything's fine here so I'm sure nobody needs me right now. When was the last time I went on an adventure?' 

Steven smiled to himself as he made his decision. He quickly texted his friends and family telling them that he was going on a trip and that they probably wouldn't see him for a while.

"Well Lion, time to go on an adventure!" Steven cheered. Lion roared, and Steven took that as him saying he's excited as well. He claimed on lions back and they stood on the warp pad.

"So does it work the same way or-" Steven didn't get to finish his sentence as the gateway activated and he and Lion were transported to a new world.