What exactly is a demon?
They're cunning, they're wicked, brimming with power to grant a summoner's every wish—only to drag their soul straight to hell.
But in a monotheistic worldview, "all glory belongs to the Lord." God is the creator of everything, the source of all power. So, demons—these evil, scheming enemies of God—must also come from His hand.
Why would God create His own enemies? It's not a tough question. Demons weren't always His foes; they were His servants. Tainted by evil, they fell from heaven, left to scrape by in the pits of hell.
Every demon is a fallen angel.
Mephisto ambushed Foras, ripping out its heart and swallowing it whole. This gruesome scene played out right in front of Okuni and the Chaldea crew.
"What… the hell is this?"
The sight before them was beyond comprehension. Foras, the thirty-fourth Demon God, a blazing stag whose hoarse voice never spoke the truth—was it just a part of Mephisto?
As if hearing their thoughts, Mephisto wiped the blood from his lips and chuckled. "Fooled ya, didn't I, Raum?"
It wasn't Foras. Foras had never even existed in this Singularity. But how could that be? If a demon impersonated another, its true name would unravel, wouldn't it?
"There's only one explanation," Holmes said, gripping his pipe as he laid out the sole truth left after ruling out the impossible. "Mephisto isn't a demon at all."
All demons are fallen angels.
But in the legend of Faust, Mephisto stands out as… different.
Its true name lacks distinction, almost a catch-all for every demon. It made a pact with Faust, granting countless wishes in exchange for his soul, but with a bizarre condition: the price could only be claimed when Faust was truly satisfied. The effort and reward didn't even come close to balancing.
And in Goethe's epic poem, Mephisto, a demon, freely enters heaven, chats with God, and makes a wager. Fallen angels are banished to hell for their sins—how could one just waltz back into heaven?
So, Mephisto isn't a demon. That's not its real name, just a title it uses when playing the part. The real Mephisto is something stranger, a being caught between angel and demon.
"Cor~rect," Mephisto grinned. "Didn't expect you to figure it out. Even that saint saw through my nature and still got played like a fiddle. Though, to be fair, Heroic Spirits like her aren't exactly known for their brains."
"In Jewish texts," Holmes continued, "there is a being who's both demon and angel."
He revealed Mephisto's true essence: "Its fall was due to God's oversight, allowing it to retain its role as the 'Angel of Trials' even after becoming a demon. It embodies both good and evil—a judge who condemns the wicked and a tempter who lures the righteous to ruin.
"This angel is known as the 'Blind God,' tasked with guiding the souls of the dead and judging their virtue.
"That's right, the 'Blind God'—the one without light in its eyes, the one who shuns it! That's the origin of the name Mephisto!
"Your true name is—Death Angel, Samael!"
At this brilliant deduction, Mephisto tucked his cane under his arm and clapped.
It was the truth. The only explanation for how Mephisto could casually bargain with God, wagering on tempting souls to fall. The only reason a demon could stand unscathed in the face of Georgios's exorcising Noble Phantasm.
But it wasn't the whole truth. The Mephisto of the Faust legend isn't the real Mephisto. That Heroic Spirit appeared in an earlier Singularity, a homunculus created by the mage Faust.
Mephisto once told Nero, "This name was given by a book." It hadn't lied about its name. It was always Samael, but as an angel, it couldn't be summoned by the Grail. So, it borrowed the name "Mephisto" from the Faust story to manifest here. The Mephisto standing before them was a fusion of the Phantom "Mephisto" and the Angel "Samael."
Since the Mephisto identity was a lie to begin with, it could lean into its "liar" persona, crafting a fake Noble Phantasm and another false identity. It poured most of its power into the fabricated "Foras" to deceive the Singularity's creator.
It lived up to its name. Not only did it fool Chaldea and Nero, but it also duped the Demon God Pillar itself. It tricked everyone in this Singularity.
But it was too late. Holmes unraveled the mystery too late. Ritsuka and the others would never learn this truth, and whatever Samael's true goal was, no one could stop it now.
"Goal?" Mephisto laughed at Mash's question, like a teacher eyeing a failing student. "Didn't that saint already spell it out?"
A trial.
Since it was summoned here, it would put everyone through a trial.
"I keep adding weights to both sides of the scale, just to keep it balanced."
Only when good and evil were evenly matched, when the clash was brutal enough, could the trial hold meaning.
"That saint did a decent job, but faith alone won't pass my test."
Mephisto wanted more than sacrifice, more than resolve.
"If I don't see the brightest spark in your souls, I'll devour everything."
Not just Ritsuka—every person, every Heroic Spirit in this Singularity would have their soul claimed.
And Mephisto was confident it had stacked the odds to ignite that spark.
Looking at Okuni's bewildered face, it shrugged. "Not talking about you. I don't expect a kid like you to clear my trial.
"A trial…"
It turned, waving a hand to command the demons to face the coast.
There, a figure charged in on a chariot, blazing toward them.
"…is for a hero to complete!"
The Heroic Spirit roared, crashing into the demon army.