That Day When Suzuki-kun Wasn't the Mob-B!

”You’re following me?” Finn asked, glancing sideways at Sairaorg. The massive, muscle-bound heir of the Bael Pillar had casually boarded the exact same magical train carriage heading toward the Gremory territory.

”It’s fine, right? Traveling alone is boring,” Sairaorg grinned, crossing his thick arms. ”Besides, it’s been a while since we last hung out. You’ve been holed up in your territory this entire time.”

Sairaorg didn’t have many genuine friends. In high-society Devil culture, developing bulging, calloused muscles was viewed as barbaric and inelegant; true nobles relied entirely on their innate Demonic Power. While Finn also utilised Demonic Power, his physical combat prowess was light-years ahead of the typical arrogant weaklings populating the Underworld. Sairaorg genuinely considered him a friend and had missed his sparring partner.

”If I visit you, I just have to watch you work out all day. I’m not idle enough to sit around watching a grown man sweat,” Finn replied dryly.

He turned his attention back to the holographic display hovering over his table, actively reviewing the data streams of his rapidly expanding investment portfolio.

The geography of the Underworld was immense, heavily favoring sprawling, continent-sized landmasses over oceans. To a corporate mastermind like Finn, it was an absolute goldmine for aggressive land consolidation. By systematically acquiring, restructuring, and merging smaller, fragmented territories from bankrupt nobles, he was creating highly efficient, centralized commercial districts. It was the ultimate strategy for high-yield financial diversification. While other High-Class Devils wasted their centuries squabbling over archaic pride, Finn was busy establishing literal cash-cow business models across his newly consolidated properties—everything from lucrative real estate developments to high-end magical vehicle dealerships.

The Underworld...

Finn looked out the train window at the passing scenery, bathing in the purple hue of the artificial sun—a marvel of engineering created by the greatest minds of their race. It made him deeply ponder the strange, hidden mechanics of this reality.

Who originally created all of this?

He highly doubted it was the Biblical God, at least not directly in this specific universe. Nor could it be the ultimate cosmic entities like Great Red or Ophis; despite their absolute, world-shattering power, their actual intellects were comparable to newborn children.

So, who was it?

Finn suspected that an ancient, primordial civilization had once existed here—a society where both science and magic had reached an absolute, hypothetical ceiling before being violently wiped out. According to his highly optimized, reincarnated memories, he knew the truth about the Evil Pieces. Ajuka Beelzebub hadn’t invented the reincarnation system from scratch; he had reverse-engineered it from fragmented, lost technology excavated from the deepest ruins of the Underworld.

That’s probably why Grandpa Zekram is so obsessed with collecting ancient books and antiques, Finn realized.

The true history of their world had been hidden, erased, or simply vanished into the abyss.

While others constantly preached about focusing on the future, Finn understood that true, systemic power lay in unearthing the past. His mythical King Piece was living proof of that lost technological ceiling. It proved a vital theory: you didn’t have to rely entirely on the genetic lottery like Sirzechs and Ajuka. With the right technology, systemic cheats, and calculated modifications, the biological limits of a Devil could be shattered.

Well, at least I have Senjutsu and my ’Self-Made’ adaptation, Finn calculated silently.

Between the massive energy reserves granted by the King Piece, the natural life-force manipulation of Senjutsu, his absolute adaptation, and his flawless Absolute Redaction (Invisibility), he was practically immune to 99% of the creatures currently breathing in this universe.

He was incredibly secure. But through the multiverse network of his Manager, he knew the other Suzukis—like the ones surviving in the brutal universes of Solo Leveling or Naruto—were constantly fighting cosmic horrors and required his tactical data processing.

I’ll be fine here, Finn reassured himself.

The ultimate endgame enemies in the High School DxD universe were apocalyptic entities from an alternate timeline or the dimensional gap, but those threats were still years away. To Finn, there were no ’destined enemies.’ There were only assets and liabilities. If someone was useful, he would tolerate their flaws and protect them. What if they lost their value and became a liability? He would ruthlessly cut them loose without a shred of mercy.

Operating like a psychopath was highly more comfortable, as he had no emotional baggage, but he had to admit that he still genuinely cared for the few people in his inner circle. The world would be incredibly dull if he entirely lost his heart.

”But we can fight!” Sairaorg’s booming voice suddenly shattered Finn’s internal monologue.

”...I literally have zero intention of participating in the Rating Games. Why should I fight?” Finn sighed, dismissing his holographic spreadsheets.

”What?! You seriously don’t want to enter? Why not?!” Sairaorg panicked, leaning over the table. To Sairaorg, the Rating Game was the ultimate proving ground—the absolute pinnacle of existence for a High-Class Devil! ”Are you honestly okay with being looked down on by all those arrogant pieces of trash?!”

Unlike Finn, Sairaorg was deeply frustrated by the current generation of young nobles. They were utterly incompetent, relying entirely on their family names while pretending to be untouchable elites.

”I’m perfectly fine with it,” Finn replied smoothly, resting his chin on his hands. ”Because I can make them beg on their knees and apologize like dogs without ever lifting a single finger. If an arrogant High-Class Devil causes me trouble, I don’t challenge them to a public fistfight. I quietly buy out their family’s debts, foreclose on their ancestral estates, and evict them into the streets.”

Finn smiled, a cold glint in his golden eyes. ”Financial ruin is a vastly more elegant and permanent revenge than physical violence. If you beat them up in an arena, they just heal in a hospital and plot their revenge. If you freeze their assets and make them homeless? They cease to exist.”

”....”

Sairaorg opened his mouth, then slowly closed it again. He couldn’t refute a single word. Finn operated on an entirely different, terrifyingly practical plane of existence. Yet, despite Finn’s mindset, Sairaorg still possessed a burning, undeniable urge to fight him on the grandest stage to definitively prove who was the strongest.

”Honestly, instead of begging me to join a glorified sports league, I thought you’d ask me to teach you my martial arts,” Finn noted.

”No, it’s fine. I know I’m not smart enough to actually comprehend your martial arts,” Sairaorg answered bluntly.

”...”

Finn blinked. Hearing such absolute, unashamed honesty from a proud Devil was surprisingly refreshing.

”That’s exactly why I have to polish my own raw strength to its absolute limit,” Sairaorg declared, his fists clenching with renewed vigor. ”I definitely won’t give up. Even if you don’t care about the Rating Games right now, I will find a way to make you participate!”

”Oh? How do you plan to do that?” Finn asked, genuinely curious how the meathead planned to force his hand. To Finn, the Rating Game was nothing more than a heavily monetized sporting event created by Ajuka to entertain the masses and generate betting revenue.

”I’ll make you a deal! When I become the Great King of the Underworld, I will let you completely manage the entire economy!” Sairaorg declared with a massive, booming laugh.

”...”

Finn stared at him deadpan. Politically speaking, there was a zero percent chance of Sairaorg ever becoming the Great King. Lacking both the Power of Destruction and a massive Demonic Power reserve meant the conservative council would never accept him, not even as a puppet ruler.

But Sairaorg’s sheer, blinding potential and unbreakable willpower were undeniable.

”I’ll think about it,” Finn replied softly.

”Yeah!” Sairaorg grinned, reaching across the table to grab Finn’s shoulder and shaking him excitedly.

As the magical train began to decelerate, the sprawling, opulent skyline of the Gremory capital came into view. The grand stage was set. They had officially arrived for the high-society event of the decade: the engagement party of Rias Gremory and Riser Phenex.