During the Great War, the four Great Satans and the God of the Bible lost their lives, leading the three factions to retreat and enter a cold war that persists to this day.

However, after about a century, the devils had a civil war, dividing them into two factions and reducing their numbers further. The factions split due to the descendants of the previous Satans, who still held a war-hungry mindset.

These descendants, calling themselves the Satan Faction, wanted to continue the war despite being on the brink of extinction. In opposition, a faction was formed, known as the Anti-Satan Faction, who believed the war was pointless and advocated for waiting until they had enough manpower to proceed.

The factions fought politically until the House of Asmodeus ordered the extermination of the Satan Faction, sparking a civil war. The Old Satan Faction was eventually defeated by the rebelling Anti-Satan Faction.

Since the newly appointed Satans were killed in battle, the leaders of the Anti-Satan Faction were elected as the new Satans, crowned as Lucifer, Leviathan, Asmodeus, and Beelzebub. They reunited the Devil World, working toward peace.

Meanwhile, houses and devils, mainly the nobility who supported the previously killed Satans, came together to form a new faction called the Old Satan Faction. This faction was tightly controlled by the House of Bael for unknown reasons.

Within this faction, two groups formed: one remained in the underworld, causing trouble, while the other fled to various places, vowing revenge.

Most of those who fled joined an organization later known as the Khaos Brigade. Although it was said to be led by Ophis, the Ouroboros Dragon, the true mastermind was Rizevim Livan Lucifer, a descendant of the original Lucifer.

Rizevim was an odd devil, even among devils. He had no hunger for power, only a desire for chaos and destruction, making him a threat to many factions. As a result, there was a large bounty for any information on him. Why not for his head, you ask? Well, it's because he is too strong for normal bounty hunters to handle. As the first-ever Super Devil, his name struck fear into all, especially after it was discovered that Sirzechs Lucifer, formerly Sirzechs Gremory, was also a Super Devil.

As maniacal as Rizevim was, he was also a brilliant researcher. Even Azazel had to show respect for his talents. However, his research was naturally of a nature that few would appreciate. His current project was recreating the 72 Pillars. But unlike his father, he wanted to create individuals who could harness the full power of each pillar.

For this, he found a suitable experiment subject, which led to the current situation.

Rizevim stood before a test capsule, inside of which was a girl, around five years old. She had silver hair and a doll-like appearance that might have tempted some less-than-moral individuals (lolicons).

Rizevim couldn't believe his luck in finding this specimen. Just as he was about to leave the underworld, he discovered her in one of the hidden chambers of the castle. According to the research papers he found there, this girl was supposed to be the trump card his father had created for the war. Unfortunately, his father never got the chance to use her.

Rizevim took her with him to investigate what made her so special, and to his astonishment, she was perfectly compatible with all the powers of the 72 Pillars. Thanks to her, his research had progressed significantly.

However, Rizevim never imagined that this girl was more special than even he realized. She wasn't just an experiment. She was the daughter of the original Lucifer and a fallen angel. A perfect hybrid that broke the balance. And if that wasn't enough, she was also our protagonist, Yumina Akihito.

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**Yumina POV**

'Argh, that old hag! Did she really have to shove me out like that? I mean, it's a new experience, sure, but WTF... Argh… Wait, where the hell am I? Why do I feel like I'm drowning, and why can't I open my eyes?'

\[Master, I am actively restricting your body. If you move even a little, you might be immediately captured.\]

'Wait a minute… that voice… Ciel? Is that you?'

\[Yes, master, I am here.\]

'So, um, Ciel, where am I right now?'

\[From my analysis, it appears we are in a laboratory. The energy signatures I have detected suggest that we've been captured by devils. The one leading them has an energy signature similar to yours, master, meaning he is likely one of your relatives.\]

'Relative? That's impossible. I wished for my lineage to be connected to Lucifer, so the only relatives I could have would be Vali or… Oh no… Ciel, can you use universal detection without alerting anyone?'

\[Yes, master.\]

Soon, the darkness clouding my vision faded, and I could see my surroundings. Only one word came to mind: 'A torture lab.'

There were various containers, all housing different creatures—angels, demons, and youkai. In front of my capsule stood a man with silver hair and a matching beard. Isn't this Rizevim, the hidden boss of *High School DxD*?

'Ciel… the relative near me… It's not him, is it?' I asked, already knowing the answer.

\[Yes, master, it's him.\]

'Sigh… So he experiments on his own family. Typical. This is the guy who killed his son just to get his grandson to awaken his Sacred Gear.'

After a round of sarcastic praise for Rizevim, I asked Ciel something I was curious about.

'So, who am I to him?'

\[My analysis indicates that you are the daughter of the original Lucifer and a fallen angel, making you his half-sister.\]

'Half-sister, huh? Not ideal, but who cares? I just wanted the versatility of being a Lucifer.'

'Ciel, can you create a status screen for me?'

**Name:** ?????

**Race:** Hybrid Devil/Fallen Angel

**Father:** Lucifer

**Mother:** Azrael

**Bloodline:** Lucifer Devil Bloodline, Lucifer Angel Bloodline (sealed), Azrael Bloodline (sealed)

**Legacy:** Angel of Death (sealed), Ruler of the Underworld (sealed), Successor to the God of the Bible (sealed), Void Empress

**Magic:** Death Magic (sealed), Demonic Magic, Holy Magic (sealed)

**Skills:** Power of Death (sealed), Soul Sear (sealed), Weapon Creation, Void God Azathoth, Manas Ciel, Heaven's System Administrator (sealed)

**Mana:** Ultimate Class

**Strength:** Lower Class

**Connection:** Lucifuge (sealed due to restraint)

'Wow… I'm a lot weaker than Rimuru thanks to that goddess messing with me, but with Void God Azathoth, I should be able to survive anything. Still, I'm surprised I'm the daughter of the Angel of Death. She was never mentioned in the novel or anime… I guess she died during the Great War.'

'What the hell is up with my magic stat? I know the Lucifer bloodline grants a lot of demonic power, but this is ridiculous.'

'Hey, Ciel, what does that "Legacy" thing mean?'

\[It refers to the titles you'll inherit from your parents. Since your father, Lucifer, was the first angel God created, he was the successor to Him. Additionally, due to your Lucifer blood and your high affinity with souls and the void, the underworld has chosen you as its ruler. Your mother, Azrael, was the Angel of Death before she fell. With her position vacant due to the Great War, you are her successor as well.\]

'Ciel, what does that "Connection" section mean?'

\[It indicates that the Lucifer house has a soul contract with the Lucifuge house, so as a Lucifer, you naturally have a Lucifuge by your side.\]

'But I thought the Lucifuge household was destroyed.'

\[Negative, master. It appears there are three remaining members of the Lucifuge household, and only one is compatible with you.\]

'Wait a minute… In the novel, there were only supposed to be Euclid and Grayfia. So who's the third person? Don't tell me that goddess added another Lucifuge to match my origin.'

'Ciel, can you locate this Lucifuge?'

\[Yes, master. Her mana signature is coming from the human world.\]

'Well, that means my next stop is the human world. Ciel, can you use Spatial Domination from Void God Azathoth to teleport me near her?'

\[Okay, master, but I recommend staying here for a few days due to some outside interference.\]

'Hmm… Why is that, Ciel?'

\[I've detected foreign substances inside your body. I believe you can gain new powers by fully integrating them.\]

'How long will that take?'

\[About three days, master.\]

'Sigh… Looks like I'm stuck here for a while.'

I thought to myself, wondering what to do for the next three days. As if on cue, the door to this cursed room opened, and Euclid walked in.

"Rizevim-sama, our spies managed to locate a Belial descendant in Kuoh. Her name is Clariel Belial, cousin to Diehauser Belial, the current Rating Game champion."

Rizevim turned around, a wicked grin on his face. "Oh, that's good

news. I was just thinking of searching for some materials."

Euclid asked, glancing at his notes, "How is the experiment going so far, my lord?"

Rizevim hummed in thought. "For now, she's very stable, even after we infused her with the bloodline abilities of the Power of Destruction, the Power of Time, and Hellfire regeneration from the Phoenix, Chronos, and Bael clans. If my estimates are correct, our test subject may ascend to the Super Devil rank without any training. And if that happens, my other project will also be completed."

Euclid nodded. "She should be a fine prototype, but Rizevim-sama, would this girl even survive? It would be a huge waste if we destroyed her by being too hasty."

Rizevim considered this and agreed. "Yes, it would certainly be a waste. I'll hold off on more extreme experiments until we find a replacement."

Changing the subject, Rizevim asked, "So, how's my grandson doing, Euclid? Did he die fighting a wild animal or something?"

Euclid chuckled at his lord's dark humor. "Sadly, no. He didn't encounter any wild animals, just a foolish fallen angel. That idiot thinks he's free just because Azazel took him in. Shall I finish him off?"

Rizevim waved his hand dismissively. "Don't bother. Let him live. Who knows, he might produce some fine specimens if he ever gets laid."

Euclid nodded, about to leave, when he suddenly remembered something. "Ah, Rizevim-sama, the Tepes faction has agreed to ally with us. Will you go there to finalize the deal, or shall I handle it?"

Rizevim thought for a moment before answering. "No, I'll go personally. I have some free time before we capture the Belial. And it would be easier for us in negotiations if I were there."

Euclid bowed. "Then I shall prepare for your departure," he said, and with that, he left.

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