A Loophole
The contract was sealed and it can never be undone unless the party concerned doesn't value his/her life.
The Abyssal Lord is here to stay, and whatever he does in this world is anyone's business no longer.
“The contract has been made, and demonic contracts can't be broken unless you value your lifes”
Xeron spoke to Ophis, Red and Grayfia after the contract bound all four of them, and seemingly remembering something begins walking towards Grayfia.
The maid sees this and doesn't react, she doesn't feel the need to, now that they're both bound to a contract that states he won't hurt her while she's his maid.
“Ajuka, can you remove this ‘queen piece’ from her, I don't share”
This causes Sirzechs mouth to twitch, but he doesn't protest as he knows it's impossible,and surely enough Ajuka confirms it.
“No, evil pieces can't be removed from devils while they are alive or they die”
And then silence, the devils didn't speak a word after Ajuka finished, to those who are familiar with the evil peices system knows that a servant can't go against their master without paying a price and Grayfia certainly won't betray Sirzechs.
That means this was a setup, the devils true to their name let Grayfia be taken to monitor the demon, without the need for violence and what's even better is that he made it even easier by stating in the contract that he won't hurt her.
…But after finding all this out the demon was calm, really calm, and the vicious smile creeping up his face holds no well intent
“Ahhhhhhhhh”
A vicious scream from Grayfia followed by her clutching her head and dropping to the ground on her knees
“Garyfia!!”
Sirzechs hurries to her side, while the other Satans open their mouths agape at this.
“How are you still alive!!, Isn't this a breach of contract, you're clearly hurting her!!”
Ajuka practicaly screams as the sound of Grayfia's screaming nearly drowns out his voice.
“Oh No I'm not hurting her”
The demon moves his head left and right calmly while still smiling.
“I'm just injecting something in her mind, that's completely non harmful to demons don't know about devils though, didn't know it'd be this painful”
Xeron face nearly spilts vertically from his smile, and to the horror of the devils, it seems that not only them deal with contacts.
“A bunch of children playing house, think they can fool me”
The sarcasm is practically dripping from each word as the demon speaks while he makes his way to Grayfia.
As he reaches her she stops screaming and he points at her and she floats in front of him.
“It's funny you thought that I wouldn't have expected this from you, hell I even from a scheme coming my way from the Dragons, but it clearly wasn't them that schemed against us all these wears ago”
He reaches his hand that's still adorned in armour and plunges it into her stomach, but unexpectedly it passes right through, swirling inside what seems to be a void as if looking for something, and a second later he pulls out a queen chess piece from inside her and hands it to Sirzechs.
“Here, take your queen”
He turns around and walks toward the Satans, leaving Grayfia to fall to the ground.
While walking his face morphs, his once milky white skin turns into dark scales, his golden red eyes turn into pure a pure black eye with blood red irises, two jet black horns grow out from his head and his teeth multiply by the thousands, lining up side by side in his mouth.
When he reaches in front of the devils, he towers over them by nearly a meter, and as he looks down at them and smiles, they find themselves staring at the ground, not daring to meet his gaze.
“As this is the first time we interact I'll forgive your little mistake”
His voice transforms with every word growing ever lower and lower, and by the end of the sentence it becomes akin to a monster from the depths of the underworld.
“But if you think ever you can pull something similar a second time”
Xeron walks to Serafall and holds her chin and force her to look into his eyes
“I'll personally rip and tear your little realm until nothing is left behind”
The Satan devils, including Sirzechs who is still standing next to Grayfia shiver visibly, while Serafall, the one he's personality holding shiver uncontrollably while tears and snot are streaming down her face and seeing this the monster smiles even wider.
“Will I believe the lesson has been delivered”
Xeron lets go of Serafall and walks away while reverting his transformation, and when he reaches back to his original position he turns to the devils again and stands there in silence seemingly waiting for the group of devils to compose themselves.
And when they're done he begins to speak
“I'll be going back to the Abyss for now, once I finish my business I'll go to where my is currently to collect her”
The four Satans, now semi-collected, processed the information, and after a second Sirzechs was the first to speak.
“Xeron, would you kindly tell me when you'll be back, I'll have someone fetch you to the Gremory household”
“No need I'll be teleporting directly next to her life signature, we're bound by souls now, I can sense her wherever she may be”
The demon's body begins to ignite in flames and before he completely disappears he announces to everyone in the room
“Then this is farewell, for now”
And after a whirlwind of flame he vanishes, like he was never there before.
And another silence follows, and it continues on for about a minute with no-one moving, including poor Grayfia who'll still on the ground, and seemingly cured from the trance Sirzechs was the first to react.
“Grayfia are you alright? What happened to you?”
The crimson devil speaks with care in his voice, albeit the care of a master towards his servant, but still care nonetheless, and offers his hand for Grayfia to get up from the ground.
“...I-I’m fine Lord Sirzechs, the excruciating pain is gone”
Grayfia takes her ‘Lord’ hand and gets up, still clutching her head in the pain's aftereffects she speaks again.
“...I-I was fine a second and a second after that I felt something probe my mind and forcefully inject a spell into it, and after that my head felt like it was going to be split in half”
The four Satans fell silent in front of this revelation, mind spells are not uncommon, especially among the succubi and incubi, which aren't under the rule of the four Satans but still devils nonetheless.
Then that implies that the demon used a mind spell on Grayfia to harm her in someway, then why wasn't he died like the so-called contact entailed he would, the only answer to this question is that the contract is fake.
“I can practically see it in your eyes young devils, the contract isn't fake.”
Only when the rough voice of the old Great Red resounded again did they remember that they two strongest beings in their world are still here.
“And what you did wasn't very smart, schemes are meaningless in front of absolute power, and that's not counting your inability to scheme against your adversary in the first place, simply due to differences in wit”
Red speaks again as he and Ophis make their way to the devils, and while Ophis went to Grayfia to heal her Red spoke to the Satans.
“Then if the contract is a real thing, why didn't it affect him when he harmed Grayfia, while It clearly stated that he can't harm her while she's still his maid.”
Ajuka seriously speaks while tapping his right foot on the floor, which he tends to do while thinking about something, to which Great Red replies while smiling pityingly.
“Not all demons are bloodthirsty barbarians, some of them are quite scheming with Xeron the Prince of Despair being the most scheming of them all”
He stops for a second to collect his thoughts and speaks again.
“You devils also do contracts correct? Mostly with humans, but you still do, well the difference between both contracts is that demonic contracts binds the parties involved to a some of clauses that must be followed absolutely, while devils contracts offer a service for a price”
The devils nod in acknowledgment, and wait for Red to continue.
“And here's the catch, the contract doesn't care about the methods employed to follow said contracts clauses, it only checks single mindedly if the parties bound follows them”
“For example what Xeron just do, the contract said to never hurt the individual named Grayfia Lucifuge while she's still his maid, well he most likely did something that's not considered hurting her from his perspective and as the contract binds him to not hurt her and he sees this as not hurting it wouldn't punish him”
“But now that he knows that what he did is hurting her he shouldn't be able to do it again, but he'll probably use a different method next time”
The devils looked tense, while the Great Red shrugged and continued speaking
“Anyhow, you should probably compensate him to avoid his wrath or at least apologize to him”
A magic circle started glowing at his feet.
“Until we meet again”
And he teleports away, and they turn to Ophis and Grayfia to find Grayfia on her feet seemingly unharmed and perfectly healthy, while a teleportation magic circle glows under Ophis's feet.
“Farewell devils, and good luck”
And she departs, leaving behind a band of troubled devils.