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Spade Kingdom:
Currently, in one of the rooms where Nacht and Jack were fighting Dante, an explosion occurred, breaking the wall of the room.
Nacht and the others turned towards the hole only to spot Magna, Luck, Zora, and Gauche entering through it.
"Hm? More worthless cockroaches? Didn't I almost kill you last time?" asked Dante with a smirk, looking towards Gauche.
"You sure did a number on us. We are here to pay you back a hundredfold for what you did to our squad and captain," replied Gauche.
"Such strong magic! Let's fight and kill this guy!" declared Luck enthusiastically.
"Oi oi oi. Don't you feel the terrifying presence of him?" asked Zora.
"Doesn't matter, my man Zora. We will still kick his butt," said Magna.
"I am not your man," replied Zora.
"You all?! What are you doing here?! It's too danger—" yelled Nacht.
[Gravity Magic: Presence of the Demon King]
Mana pressure crushed the room, cracking the floor.
"Your heads are too high. Kneel."
[Mirror Magic: Mirror Trap]
A giant mirror formed above Gauche, soon shattered, and began absorbing the gravity magic in the surrounding area.
Once all the magic was absorbed, the mirror fixed itself and became smaller, floating beside Gauche.
"Same tricks won't work against me again," replied Gauche firmly.
"Heh, we will se-" started Dante, however, an instant later, a bolt of electricity crackled beside him.
[True Lightning Magic: Lightning Battle Fiend + Keraunos]
A lightning-fast kick landed on Dante, sending him flying.
Luck bolted once again, appearing above Dante and slamming him to the ground as mana method arrays formed in his hands.
"You speak more than you fight," said Luck with a 'smile' as a large amount of electricity gathered in his hands.
[Ultimate Lightning Magic: 100 Million Volt Death]
Dante's eyes widened in shock, sensing the sheer amount of mana contained in the spell.
The same was the case for the fellow magic knights, who were not expecting such power from Luck at all.
Without hesitation, Luck fired the attack at the Devil Host.
Dante tried to use his magic to blast Luck away, but before he could, a mirror appeared beside Luck.
"Want to see something familiar?" asked Gauche with a smirk.
[Mirror Magic: Presence of the Demon King]
Gravity magic trapped inside the mirror burst out, pushing Dante even more as the massive lightning spell blasted him through the ground, making him crash through multiple floors.
The entire building shook because of the attack, making the injured Nacht and Jack stumble and fall, while the other Black Bulls somehow maintained their balance.
"Oi! Lightning freak! Do you want to crush all of us in the rubble?!" asked Zora with annoyance.
"Damn you, Luck! When the hell did you learn that outrageous spell!!!!" yelled Magna.
"Haha!!! That was amazing!!! It was my first time using that against an enemy!!!" laughed Luck.
Lightning crackled once again as mana method arrays started forming above Luck's hands.
"Let's do it again!!!!" yelled Luck, high with excitement.
[Gravity Magic: Dark God's PressureCraft]
The ground around Luck broke and rushed toward him, making the lightning mage bolt away from his spot.
"Even that didn't end that devil bastard," muttered Jack.
From the hole came a super-charred Dante, smelling of burnt meat and blood dripping from various parts of his body.
His body's magic immediately started working at maximum as his body began to heal rapidly.
"The Black Bulls keep on surprising me time and time again. But all that is useless now. With my Devil power at 100%, I—" yelled Dante.
At that moment, something unexpected happened. The black devil markings on Dante's body, along with the devil wings and features, disappeared out of nowhere.
"...Huh?" muttered Dante, feeling power drain from his body.
He checked himself and found none of the devil markings.
The Magic Knights were shocked by the sudden change as well; however, a voice broke them out of their stupor.
"Yo, Funky Beard Dark Triad," called Zora.
Dante looked toward the red-haired masked man, who gestured for him to look down.
Dante did the same, only to realise that he was suspended above the hole where Luck blasted him.
"...Fu—" muttered Dante, and gravity decided it was time to work again, making Dante fall.
The Magic Knights didn't know what had happened, but they knew that for now, Dante was neutralised.
"What the hell happened just now?" asked Jack, looking toward the Black Bulls, who looked at each other and shrugged.
They then turned to Nacht, the most knowledgeable among them.
"It seems Dante lost his Devil powers all of a sudden. It can only happen when either his connection with Lucifero got broken somehow, or the Devil giving him power forcibly undid the transformation..." muttered Nacht.
He pondered for a while before turning to his own devils.
"Do you guys know something about this?" asked Nacht.
"We are not sure, but earlier we saw that Sekke guy slash open the entrance of the Tree of Qliphoth and go inside it," said one of the devils.
"Meaning he is in the underworld?" asked Nacht.
The devils nodded, confirming Nacht's suspicion.
"Yup. That sums it up," said Magna.
"Sekke must be having so much fun there!!!... I wanna go too!!!" exclaimed Luck and tried to run away, only to be held back by Magna, who grabbed him by the collar.
"Where the hell are you running off to? We need to save Yami-san right now."
"Ah! Right! Let's go save the Captain, and then all of us can head off to where Sekke is!!!"
"That's not a picnic spot, you know," said Zora.
"I am not going there. After saving the captain, I am heading straight to see my angel Marie!!!!" declared Gauche.
"..."
Nacht didn't know what to say. His squad mates suddenly got strong so quickly, and one of them went to the underworld and is somehow undoing the Dark Triad's devil union.
"...That brute put together a squad of complete weirdos," muttered Nacht.
"Agreed," replied Jack, heading towards the hole where Dante had fallen and jumping down to deal with the Dark Triad and ensure everything was under control.
"You all head to save Yami. I will go and check on the other Dark Triad and the Dark Disciples," ordered Nacht, following after Jack.
Magna and the others nodded and ran toward Yami's location.
Meanwhile, at other locations within and outside the Spade Kingdom Castle, the Dark Triads and the Dark Disciples somehow lost their devil powers as well—except for Zenon, who had asked his devil to implant a devil heart in him, allowing him to use devil powers on his own.
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Underworld:
A few minutes before the Dark Triad and the Dark Disciples lost their devil powers, Sekke and his army were causing a rampage in the underworld, making the devils or the devil who was smart enough to surrender thank his quick thinking.
[Devil Earth Magic: Meteor Fall]
A high-ranking devil used his magic, making the sky tear up as a massive meteor came out of it.
"Take that human!!!" yelled the devil.
"Glady!!!" yelled the armour-clad Sekke who flew towards the falling meteor with Extase in his hands.
Extase's blade shimmered out of existence, and a moment later, the meteor split apart before disintegrating into nothingness.
"N-No way," muttered the devil in disbelief, seeing his strongest spell destroyed this easily.
A shadow soldier appeared beside the devil.
[Gem Magic: Brilliant Doom- Garnet]
A reddish purple gem manifested in the shadow hand before exploding in the devil's face, destroying him in an instant.
[Arise]
Sekke called out, and his shadow rippled as the devil in the form of a shadow came out of it.
"...That's a really unfair spell," muttered the sole devil that surrendered to Sekke.
"That for you is the might of the Dark Lord, my new friend Adramelech," called Sekke and landed beside the devil.
The devil Adramelech looked at Sekke with his disinterested look.
'This is going totally different from what you predicted, Lucius Zogaratis,' thought Adramelech.
"Still? You sure you don't want to help your fellow devils?" asked Sekke and pointed towards the devils who were fighting against the devils.
Adramelech looked at the battlefield and shook his head.
"Too bothersome. I don't fight a hopeless fight. Not to mention. That Spirit's magic makes me shiver."
Sekke looked towards the Sun Spirit King, whose mere presence was burning the devils.
According to Vritra, the spirit for too holy for these devils.
"For the honour of My King, I will dedicate this victory to you!!!!" yelled Exodia.
[Sun Spirit Magic: Light that Burns the Sky]
Mana gathered in his hands and shot forward, brightening up the places the attack passed through.
"For My Liege!!!" yelled Exodia and fired another attack.
"For My Liege!!!" another blast shot forward.
"FOR MY LIEGEEEEEEEE!!!!!" yelled Exodia and destroyed the entire battlefield in excitement, burning away everything around them.
With allies that never died, Exodia was free to let loose, and he slowly forgot about the restraint training that he underwent.
Sekke formed a barrier protecting himself and Adramelech.
Adramelech blinked in surprise and rubbed his eyes to make sure that he was not hallucinating.
'What the hell is this power? Even I use Light Magic, but what the hell is this Light that even makes my skin crawl? I am a highest-ranking devil, but even I don't see any way to deal with this human.' thought Adramelech.
"Adramelech....how do you guys repopulate?" asked Sekke, feeling a bit bad for ending almost the entire devil race.
"We just appear in the underworld. We don't have organs for reproduction," replied Adramelech.
"Is that so? Well, anyway, shall we go further to the rest of the highest ranking devil?" asked Sekke.
"I don't think we need to," replied Adramelech and looked up.
Sekke followed his gaze and spotted the highest-ranking devils flying towards them.
Lucifero, Megicula, Beelzebub, along with a few other highest-ranking devils, finally arrived.
"YOU HUM-" yelled Lucifero
"FOR MY KING!!!!!" yelled Exodia, firing and exploding a sun near the devils, ending them all in a single attack.
Sekke and Adramelech blinked at the anticlimactic end of the devils.
"HUZZAH!!!!! MY SHADOWY COMRADES!!!!! THE VICTORY BELONGS TO US!!!" declared Exodia and fired a blast into the sky in celebration, setting off what looked like world-ending fireworks.
"Sekke Bronzaza, my friend," called Adramelech.
"Yes?" replied Sekke and facepalmed at his spirit's antics.
"If I were to seem like I am about to betray you, just slap me and remind me of this scene."
"Will do my friend," replied Sekke and patted the last surviving devil's back.