A blade in the dark

Frederick stood in front of a gigantic door, admiring its majesty. The symbols and decorations only being vaguely shown by the flickering light that came of the magical green fires that floated along the high walls. Behind him laid the broken parts of a bronze clockwork machinery that was from a time long ago, that only fell after a battle filled with hardships. But it was al worth it, this battle and the events at the Haunted Castle. All these events made sure that his plans were coming together, slowly but certain. And now he was here, close at one of the gateways that could lead them into another realm.

'Let's get going'
Frederick monotone voice echoed through the empty halls underneath the tower. And some of the remaining grunt he took with him from Savage Skull opened the door to a huge an spacious room where they even couldn't see the top.
The room itself was nothing but empty besides a tremendous arc like structure in the middle of it. So ancient that it looked like it could crumble any minute, but Frederick could feel the power flowing from it. There was no possibility that this structure would ever fall apart.
Frederick ordered his man to secure the area while he focused back on Naraku.
'So we are here..'

"Yes and soon the true battle will begin...I will gain the power of Envy...and then the other realms will fall." she said with a dark smile pulling out the keystone pieces that they had recovered. It had been a difficult task, but they had succeeded. "Remember our deal Frederik...if anything happens to me I get Savage Skull, and if anything happens to me you get Divine Torment." With that she channeled her magical power into the stones within her hand. They rose into the air and slotted together before floating towards the large gateway. As it entered the centre energy crackled from it a giant swirling vortex which was akin to the night sky opened. "The realm of Envy...is just through there. My home." Without another word she stepped through the gateway.

'Yes, our deal'
Frederick's voice echoed through the portal, his voice sounding more elegant to the other Guild Master inside the gateway. He walked over to the pedestal where Naraku had placed the keystone on and continued speaking.
'It is a real shame to lose you like this Torturess, never to return from voyage into the demon realm. But don't worry I will take care of your assets and use them to it's fullest potential, especially this one. See you in another life...girl'
After his small remark from when he met her for the first time, when she was still in her younger form Frederick grabbed the keystone from the pedestal and with it the portal started to collapse, and as it collapsed he could see the last moments from Naraku in this realm, her eyes staring at him bloodthirsty. And from under his hood a small smile appeared, not only because he had gotten rid of a rival but the fact that with the keystone he could continue his own path once again.
'Savage Skull will rise again..'

His words sounded strange and naraku had gone to leap back through the portal, but it sealed off before she could. She was trapped. Endlessly trapped in a realm fit for demons. Of course as a demon slayer this was perhaps the ultimate playground, but she could never leave. Only when all seven realms were conquered was it possible to go from one realm to another. At least for a human. The elder demons could but that was part of their power. No, she was trapped. Forever.

However, a smirk came to her face. "He will do well. And I am home."