It had been 3 weeks since the defeat of horde prime. The kingdoms of Etheria all worked together to help rebuild, along with assistance from former horde soldiers and prime clones. Though many people didn't completely trust them, the people of Etheria gave them a chance to help make the planet stronger than ever.
In the Fright Zone, Entrapta and Hordak cleaned up his lab and started putting things into storage bins. "Are you sure it's ok to stay at Dryl?" Hordak asked.
"Why wouldn't it be." Entrapta replied. As she placed some of hordak's inventions into storage bins. "I asked if you wanted to stay. And you said 'yes'."
"I did… but I'm worried what your subjects will do when I arrive."
"Don't pay attention to what other people think. You may have done terrible things in the past, but now you have a chance to make things better."
"If you say so." As he gathered more of his belongings, he stumbled upon a large grey metallic box hidden away in the corner of the room.
"Oh! What is that?" Entrapta asked with excitement as she ran for a closer look.
"I do not know," Hordak relied, "an expedition team discovered it in the crimson waste years ago. It was encased in some kind of outer shell when it was found. It was brought to me and discovered this inside it."
Entrapta examined the box closely, trying to figure out what it is. "It appears to be some sort of device. How do you activate it?"
"I've never been able to turn it on. It has stayed like that ever since I opened it."
In Mystacor, the head sorceress, Castaspella, quickly walked to the dark vault where many other sorcerers guarded the mysterious red cracked box as it began to blow again. "Any changes today?" Castaspella asked.
"Not sense that crack appeared," one of the sorcerers said.
"That box has been silent for over a thousand years. Why would it start acting up?" But as soon as she said it, the box suddenly stopped shaking and glowing.
"What's going on?" Another sorcerer asked.
Castaspella slowly walked up to the box and touched it. It then shook again and she backed up. A tubed shaped portal opened from the ceiling and someone dropped down it. He appeared to be a large, humanoid alien with pale, greyish cracked skin, razor sharp teeth and large horns that are part of his head. His arms reached to his knees, while his hands appear to possess seven fingers, each with sharp, black claws. He wore a metallic, silver armor that shifted and exposed sharp blades all over his body. He held a large axe in his right hand that had orange highlights. The sorcerers and sorceresses surrounding the box took defense positions as the large creature saw them.
"Who are you?" Castaspella asked.
The creature looked around the vault and was unimpressed. "Defenders," he began to say. "They have failed a hundred thousand worlds. They always fail."
"Who are you, and why are you here?" Castaspella asked again as former spheres of magic around her hands.
"I, Steppenwolf of Apokalypse, have come to enlighten you of the great darkness," he addressed every one, "I will bathe in your fear."
"You will find none here." The sorcerers and sorceresses readied their magic and aimed at Steppenwolf. But suddenly, a swarm of humanoid insects with blasters appeared from the portal and attacked them. A brave sorcerer tried to attack Steppenwolf, but he swung his mighty axe and was killed instantly. Many others tried to stop Steppenwolf, but continued to fall to his blade or were shot by the insectoid creatures.
Steppenwolf reached out for the box, but Castaspella grabbed the box before he could and conjured a shield spell that encased him. "Go!" One of the sorcerers told her.
"I'm not leaving any of you behind!" Castaspella exclaimed. But one of the insectoid creatures shot him as Castaspella held him in her arms till he died. She closed her eyes and ran out of the vault. Steppenwolf broke through the shield spell and chased after her.
Castaspella ran through Mystacor with Steppenwolf and insectoids chasing after her as many more sorcerers and sorceresses helped defend her and the box. Many more of them fell to Steppenwolf's blade as he killed without remorse. One of the insectoids grabbed onto the box, as Castaspella tried to hold onto it. She then killed it but dropped the box, revealing the box was encased in an outer red shell. It's true form was metallic and glowed red. Castaspella was wounded with a broken leg as she tried to grab the box. But Steppenwolf beat her to it as he picked it up.
"Oh, noble sorceress. Why do you continue to fight?" Steppenwolf asked. She looked around and saw many of her friends and comrades die with more escaping Mystacor. "You can't save them." She fired a beam of energy at Steppenwolf, but he deflected it with his axe. "The darkness begins."
Castaspella gathered her remaining strength and followed her friends to escape. Another portal opened in the air as more and more insectoid creatures came flying out. He walked into the Lunaruim with some insectoids carrying a large slab of metal. Once they set it down, he placed the box into the slab as if it was being welded. "Yes…" he said with glee "now only two remain. Go! Follow the scent of the Mother Boxes. Find the missing two. Once they are found, the Unity will be formed. This world will join the others. He will be pleased. He will see my worth again."
Down on the surface of Etheria, Castaspella and her comrades laid below the floating kingdom. "How many have we lost?" She asked a sorceress.
"Half of Mystacor has fallen, my lady." She answered.
"It can't be." She couldn't believe that half of Etheria's finest sorcerers were slaughtered like sheep. "That monster… will pay…"
"What do we do now?" A sorcerer asked.
Castaspella regained her composure and said, "We must help our wounded. Then we head to Brightmoon. We have to warn everyone."