There are two types of magic users in this world.
The first is the spirit sorcerer, like Emilia. They form contracts with spirits, drawing mana from the atmosphere through a gate and storing it within themselves. When needed, they release this mana through the same gate. The abilities of spirit sorcerers aren't influenced by the quality of their gates but are instead tied to the power of the contracted spirits.
The second type is the conventional magic user, like Roswaal. They use their internal Od (magic power), a blend of soul power and life force, and release magic through their gate. These magic users' strength is limited by the quality of their gates. Despite this limitation, Roswaal is undeniably one of the world's strongest, second only to the witches, as he can single-handedly face an entire army.
Magic in this world is divided into four basic elements—fire, water, wind, and earth—and two rare attributes, yin and yang, making a total of six. Fire is usually associated with heat-based magic, like the ice spells used by Puck and Emilia, while water magic often focuses on healing. Yin and yang are less common; yin magic often involves concealing vision or inflicting status ailments.
Roswaal possesses a blessing similar to the Sword Saint's blessing, known as the Magic Guardian's blessing, making him the strongest magician in Lugnica. He holds the highest honorary titles for mastery in fire, earth, and wind magic, known respectively as Red, Green, and Yellow.
Most critically, Roswaal is a master manipulator. Over 400 years ago, he was nearly killed trying to protect his teacher, the Witch of Greed, Echidna. To survive, he used his direct bloodline as a vessel. The longer one lives, the more twisted they can become, especially when they resort to body-snatching. Figures like Matou Zouken and Roswaal seem to confirm this notion.
Now, this twisted figure waits late into the night, and it's certainly not to welcome Emilia. Roswaal's real plan is to slay the dragon to revive his teacher, and Emilia is merely a pawn. Once she ascends the throne, the Divine Dragon Volcanica—who has a contract with Lugunica—will appear, and Roswaal is waiting for that moment.
However, he remains unaware of one crucial fact: his teacher, Echidna, isn't truly dead. She secretly made a contract with the Divine Dragon, transforming into a spirit-like form and hiding within an experimental area known as the Sanctuary, where she continues to manipulate events.
Roswaal has likely seen a new entry in the Book of Wisdom, which is why he rushed here. This magical book can reveal fragments of the future, like a downgraded form of future vision. However, the Book of Wisdom in Roswaal's possession is a censored version given by Echidna; the original is still in her hands.
The Book of Wisdom, also called the Memory of the World, holds knowledge of the world's past and future. For an outsider like Ryou, who can profoundly impact the world, there are likely entries about him in this book. Based on the complex relationship between Roswaal and Echidna, Ryou suspects that Echidna uses Roswaal's love for her to control him, feeding him information from the censored book. Roswaal's unusual behavior seems influenced by Echidna's hidden manipulation.
"As expected, the aftermath of killing Satella is becoming apparent. The hidden powers of this world have begun to notice me," Ryou muttered to himself. He had anticipated this when he killed Satella. The three individuals who initially sealed her—the Divine Dragon, the first Sword Saint, and the Great Sage—each hold a key to unsealing the Witch's Core.
After accidentally killing Subaru Natsuki, Ryou obtained the Great Sage's key. The other two are likely held by the Divine Dragon and the Astrea family. The most probable candidate for the Sword Saint's key is the Dragon Sword Reid, which Reinhard wields. It's rumored that the Dragon Sword has a will of its own, only unsheathing for worthy opponents. Ryou speculates that the soul of the first Sword Saint may be hidden within the Dragon Sword Reid, along with his key.
Rumor has it that the first Sword Saint's greatest strength was his inability to be truly killed. Upon Satella's death, those who sealed her, as well as the Witch of Greed, Echidna—who made a contract with the Divine Dragon and participated in the sealing—would surely have noticed. Even without this connection, Echidna likely knows everything through the complete Book of Wisdom.
The Witch of Vainglory, Pandora, has also probably learned of Satella's death. Although she may not be strong in direct combat, her overpowered abilities and preference for acting behind the scenes make her a strong candidate for the final boss.
Entering in Re:Zero is akin to the fourth and fifth Holy Grail Wars in the previous world—a situation where, from the start, he's been at the center of attention from all sides, as though targeted by the malice of the universe itself.
...
Eventually, the mansion quieted down. In the dark corridors, only the cold moonlight cast a faint bluish glow, turning the hallway into a ghostly realm.
At that moment, a heavy metallic dragging sound echoed faintly through the silent corridor. The sound grew louder until a figure appeared in the doorway.
Creak!
With a soft noise, the door opened, and the figure stepped inside. The room's curtains were undrawn, allowing bright moonlight to illuminate everything.
The figure was none other than a blue-haired maid—Rem! Yet, her expression differed completely from her usual gentle and humble demeanor. A small, sharp horn protruded from her forehead, her blue pupils glowed red, and her mouth curved into a ferocious smile. In the pale moonlight, she resembled a demon from hell.
In her hand, she held a morning star hammer, a head twice her size, glaring murderously at the sleeping figure of Ryou.
Ryou, seemingly exhausted, didn't stir despite the noise Rem was making.
Targeting the unsuspecting Ryou, she hurled the morning star hammer directly at him.
"Die!"
The hammer whooshed through the air with dreadful momentum. If it struck, it would surely turn any person into a paste.
Just as the morning star was about to strike Ryou, he stretched out naturally in his sleep, raising his right fist, which collided directly with Rem's weapon.
Clang!
A loud crash echoed through the room as iron fragments shot out like bullets, shattering decorations and furniture around them. The hundred-pound head of the morning star was flung into the ceiling by Ryou's punch, crashing up through to the floor above.
Caught off guard, Rem was pulled along by the force, dragged to Ryou's bedside, and ended up falling right next to him.
"Oya~ the service at this mansion is truly top-notch, even providing maid service in bed," Ryou teased, unfazed by Rem's ferocious attack.
Rem's fury intensified, her eyes glowing an even deeper red as she shouted, "You damn Witch Cultist! You maggot with nothing but filth in your head! You took away the horn most precious to me and my sister! I must kill you!"
She pulled fiercely at the handle of her morning star, but the head remained lodged in the ceiling, immovable. Upon closer inspection, she saw that Ryou was holding the handle between two fingers, effortlessly preventing her from freeing it.
"Damn it! Let go!"
Ryou shrugged and released his grip, causing Rem, who had been pulling with all her strength, to stumble backward.
It was now clear—despite her determination and strength, Rem stood no chance against Ryou. Yet she showed no signs of giving up, her heart consumed by hatred.
"Die! Die!"
Rem screamed, her eyes and horn glowing a blinding red as she swung the giant morning star toward him. Seeing her loss of control, a flicker of impatience appeared in Ryou's eyes.
Magic Burst!
Magic surged through Ryou, amplifying his formidable strength. A blood-red aura enveloped him like a thick armor. Once more, he met Rem's hammer with his fist.
This time, with a dull thud and the faint sound of breaking metal, Rem's finely crafted morning star shattered into pieces before her bewildered eyes.
Before she could react, Ryou used a technique called Shave, moving at lightning speed to appear before her. He grabbed her by the throat, lifting her off the ground.
But instead of focusing on Rem's struggle, Ryou turned his gaze toward the door.
"You've been watching for quite a while. Haven't you had enough?" he said coldly.
"Ara~ our guest is truly perceptive. Could you please~ let go of my little maid? She was just~ playing a joke with you."
With his usual odd rhythm, Roswaal appeared at the doorway, dressed flamboyantly, his face amused as he sized up Ryou.
At that moment, a searing beam of sunlight shot from Ryou's eyes directly toward Roswaal. For the first time, Roswaal's expression turned serious. Without flinching, he conjured a series of wind-elemental shields and earth-elemental walls, blocking the attack.
The beam pierced through ten shields and walls before finally dissipating.
Ryou seemed indifferent; this was merely a greeting. If Roswaal couldn't even block that, he wasn't worth any further attention.
A flicker of seriousness crossed Roswaal's eyes, but he clapped his hands with cheerfulness, hiding his true feelings.
Clap clap clap!
"That was~ a marvelous spell. So now~ would the guest kindly release~ my unruly little maid?"
Ryou scoffed.
"Stop pretending with me. You came to find me because you saw something in the Book of Wisdom, didn't you?"
For a split second, Roswaal's mask of calm wavered. Besides himself and one other, no one was supposed to know about the Book of Wisdom, even in its censored form. How could this outsider possibly know?
A moment of cold rage flickered in Roswaal's eyes. Ryou's knowledge of the book struck a nerve. For Roswaal, obsessed with reviving his teacher, the Book of Wisdom was the key, and nothing could jeopardize it.
"Now that's more like it. You want to kill me, and I find you pretty annoying too. Only one of us is walking out of here alive—simple and straightforward."
"You jest~"
Roswaal replied with a forced smile.
Ryou's expression hardened.
"You know what I hate the most? People like you, pretending to be polite while secretly wishing to kill me. So, to shatter that ridiculous mask, I'll tell you a little secret…"
He paused deliberately, watching Roswaal's attention sharpen. Roswaal's eyes locked onto Ryou, intrigued, and his usual composure wavered.
"You mentioned Emilia earlier, so I'll tell you this: I've already told her about your plan to use her to kill the Divine Dragon."
Ryou shrugged, speaking casually.
"But you know, that girl is too kind. She seems to owe you a debt of gratitude, so she couldn't outright refuse. But I think, with your sharp senses, you must have noticed something off about her attitude toward you today, right?"
Roswaal, now overthinking with suspicion, began recalling every detail of his recent encounter with Emilia. Just as Ryou hinted, Emilia had indeed seemed unusually conflicted today.
A surge of murderous intent erupted from Roswaal. To him, killing the dragon and reviving his teacher was paramount, and anyone standing in his way had to die.
"Guest, you're putting me in a difficult position~ You shouldn't meddle with my most important piece, you know!"
With that, a storm of violent, green wind blades surged toward Ryou, carrying with them Roswaal's boundless killing intent!