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- This person calls himself the "True Demon Lord." For other Demon Lords go here.
- This is the King of Greenwood as of Volume 7. For others who were the King of Greenwood go here.
Takuma Sakamoto (Sakamoto Takuma) a.k.a. Diablo (gamer tag:@Diablo-13) is the male protagonist of the series. He was a Cross Reverie player who controlled the character Diablo, known as the true Demon King. He always defeated players with better equipment and overwhelming skills, always holding back for being too strong. But one day he was invoked in another world, reincarnating in the body of his character, Diablo, finding two girls, a Pantherian and an elf, who claimed to have invoked him and that he should be a slave to one of them but due to his ring the magic back against them becoming slaves.
On Earth, he has a typical appearance of a Japanese adult human man. He wears a collar-stretched T-shirt and half-pants that were starting to fray at the cuffs.
His Cross Reverie avatar, which is also his appearance in the other world, is a white-haired Demon with black eyes that were sharp, birthmarks that looked like bluish black tattoos that went from his forehead to his cheeks, and it looked like there were two horns on his head that made him look devil-like due to the effect of 《The Distorted Crown》. With a beautiful form that overflowed with a rough charm, when his body is tensed, his skin was dark-skinned and sturdy. On his body, he was wearing pitch black clothing called 《The Hollow of Jet Black》. His back is covered by an important person's mantle called 《The Curtain of Dark Clouds》. At his waist, there was an Item Pouch. On the middle finger of his left hand, he wore 《The Demon King's Ring》. And finally, he had a staff equipped as a weapon called 《The Staff of Tenma》.
His true personality is that of an introvert who has trouble talking to women. He gets jealous of couples in the game and uses his character Diablo to annihilate them as a form of catharsis.
As Diablo, he projects a haughty persona although his true personality sometimes slips.
He was an introvert who played the MMORPG Cross Reverie as his character Diablo. He also played a bit of Sister Carnival (SisKani) and a modern warfare FPS.
One day Takuma awakens seeing two girls. He is then suddenly kissed by whom he identifies as a Pantherian and an Elf. He sits up and surveys his surroundings and notices that it wasn't his room but it seemed familiar and he was wearing different clothes than what he slept in. He then heard the Pantherian girl saying that the Enslavement Ritual ended. This triggered his memory recognizing the place they are at is the top of Starfall Tower where Summoner players of Cross Reverie go to call forth Summoned Beasts and that he was on the altar where the Summons appear. Takuma then hears the Elf girl exclaim that now she is a Summoner. The Pantherian girl retorted that she was the one who called the Summoned Beast. They argued with each other over who summoned him. He realized that he wasn't summoned as a play but as his character Diablo.
He reviews in his head on what he remembers on Summoners and Summons and worried if he was going to be dominated. He then thought it wouldn't be bad if he does by either the Elf or the Pantherian but quickly dismisses it. The Pantherian girl then goes up to him and ask if he could understand them which he vocally affirms. This surprised the girls, hearing that he could talk since Summons normally don't. They then argued again on whom summoned Diablo. They then state that they will confirm who summoned him.
On Earth as a human, Takuma Sakamoto has no outstanding abilities except for being an expert at playing video games, especially Cross Reverie. He got his character Diablo to the counter-stop level of 150 as a Sorcerer and mastered all of the Elemental magics and had the Combiner sub-class. The arrangement of his stat distribution and skills, his job-class title is 《Sorcerer of Annihilation》. When he came to the other world and became his game character, he is able to use them as well and he can even adjust it to make an ice cup filled with water appear out of thin air. Also after coming to the other world, he might have picked up the chef sub-class and may have surpassed level 150 as a Sorcerer.
He has been appraised by Emile Bichelberger as level 40 Warrior when they first fought & met. He decides to level up after facing the Fallen who infiltrated the Kingdom of Greenwood in Volume 7. In Volume 8 he trains and ate Gold Fruit to level up to get the current Master Swordsman Graham, Graham Sasara, to teach him to reach pass the limits.
- 《The Ebony Abyss》: Decreases damage taken from physical attacks and increases parameters. If he intentionally harms himself the first effect does not activate. He burns everything but the pants in Volume 5 to fuel the bonfire to save Horn from hypothermia.
- 《The Distorted Crown》: Changes the appearance of the user to have horns and automatically restores HP.
- 《The Demon Lord's Ring》: A drop from defeating the 《Demon Lord of the Brain, Enkvalos》. It has Magic Reflection and can reflect all kinds of magic whether it be an attack, support, or healing.
- Item Pouch: An item pouch Takuma bought all the upgrades using RMT.
- 《Call of Darkness》: A mantle that bestows 《Fear》 on all enemies.
- 《Angel’s Feather》: It would transfer the user’s entire party to any location.
- 《Empty Sky’s Dance》: Boots that Diablo equipped after visiting his treasury in Volume 7. They possess a Flight Magic ability but requires MP to use.
- 《Tonnerre Empereur》: A black magic staff Diablo equipped after visiting his treasury in Volume 7. Diablo can mentally command it to transform into a blade, after which the staff opens up in the middle like a pair of scissors, with the left and right sides forming a blade with a gap in the middle that has purple lightning running through it, that shapes into a plasma blade made of light. After it is transformed into a sword, it is called 《Tonnerre Emperuer • Libéré》. The weapon has an effect that activates magic or attacks seven-fold at a cost of extra expensing of MP or SP.
- 《Phantom Secret Stone》: Its effect was that for only an instant, he would be able to absolutely evade the target’s attack.
- 《Garuda Edge》: A dagger that increases HP and has a moderate chance to cut away an enemy's physical attack.
- 《Gigantes Mail》: Armor that primarily strengthened his physical abilities.
- 《Supreme Ruler’s Bangle》: Cuts damage received below a fixed value.
- 《Seraphic Sword》: A level 70 equipment. It increases experience gained.
- 《The Staff of Tenma》: A staff that increases the INT of a player and shortens chant time. He loses it in Volume 5 in his dungeon when he saved Horn from the river.
- 《The Curtain of Dark Clouds》: Prevent bad statuses. If an attack would decrease the HP to 0, it instead would leave 1 HP. He burns it in Volume 5 to start a fire to save Horn from hypothermia.
- 《Prototype War Scythe》: A melee weapon Diablo bought in the 2nd volume when he needed a way to fight someone without killing them. He saw it in the back of the weapons store and remembered that it was a rare limited item from Cross Reverie. It was destroyed in Volume 10.
- 《Omit》: Omits the charging (aria) of magic.
- 《Underwater Movement》: Allows easier movement underwater.
- 《Return》: Magic that is the basic of the basics. It allows a person or party to return to the last town they had visited.
- 《Ice》: A low-level spell that conjures and manipulates ice.
- 《Water》: A low-level spell that conjures and manipulates water.
- 《Light》: A low-level Light Attribute spell. A ball of light that flies towards the ceiling (or open air), and once it hits (or reaches a certain height), it bursts and light spreads out in the room/immediate area. This is a magic spell created by Diablo in his spare time practicing magic as a counter-measure for night warfare. He can also imbue objects with it.
- 《Fire》: A low-level spell that conjures and manipulates fire.
- 《Arm Scrap》/《Arm Break》: A weapon destroying spell. It has no effect on equipment that was greater than Rare. This means that it is restricted to weapons that have not been bestowed with magic. It has no use in Player battles, but it does have an effect in drastically shaving off the offensive ability of monsters that possessed weapons.
- 《Stardust》: Level 30 Water Type spell. A weak magic. Its visual effects (sparkling hexagonal ice crystals fluttering about) is showy. When used by a magician with a short charge time, it is possible to fire it in rapid succession in the surrounding area around the opponent to use 《Stardust》's visual effects as a smokescreen.
- 《Bit Arrow》: A spell that conjures an arrow of light and shoots out toward the enemy. Its power is low and has a high hitting accuracy.
- 《Explosion》: Level 50 Fire spell; collecting the hydrogen within the atmosphere, it ignites that spot using magical power.
- 《Flare Burst》: A superior version of the 《Explosion》 spell. It can cause a rare Critical Hit and sometimes Fumble.
- 《Air Shoot》: A spell as if a squall had blown in. It separates the opponent to a distance away from the caster.
- 《Lightning Bullet》: A high-ranking Lightning spell. A bullet of Light that is shot at the opponent.
- 《Dark Bullet》: A high ranking Dark spell. A bullet of Darkness that is shot at the opponent.
- 《Dark Press》: A spell which produces a black sphere of Darkness that is thrown/tossed at the opponent. Manipulating gravity, it would flatten enemies that were in its effect range of 5 meters. It also has the special effect of putting the enemy in a Bind status for a while.
- 《Dark Flare》: A spell that conjures a black hellfire.
- 《Dark Burst》: A spell that causes a soundless explosion.
- 《Black Lance》: A spell that summons and launches a jet-black lance.
- 《Darkness Rain》: A spell that creates Darkness arrows that downpour like black rain on the opponent.
- 《Aero Shredder》: The highest grade Chemical Element Magic of the Wind attribute under level 100. The target of the spell is wrapped up in a green flash with a thunderous roar being raised as the target is cut into pieces.
- 《Burst Rain》: Level 70 ranged spell; A ball of fire appears in the sky and bursts open together with a thunderous roar. Clumps of flame that were about the size of fists will rain incessantly on the spots the caster aimed at.
- 《Super Mine》: Level 80 Earth attribute planting-type spell; It is a trap that would break out from the aimed at the ground, and bestow damage on the opponent that passed by above it. The damage it gave was small but with its characteristics being the time until it activates being fast, it was a magic meant to bring down monsters and Warriors that were filling in the distance.
- 《Freezia》: Level 80 Water spell; putting a brake on the molecule's motion with magic, it makes them freeze. A magic that would freeze the target's range.
- 《Volcanic Wall》: Level 80 Fire and Earth spell; Flames were made to spout out from the ground like an eruption and make a flame wall.
- 《Freeze Zone》: Level 90 Ice spell; it would freeze a small targeted range. It would also bestow the speed reducing bad status 《Cold》.
- 《Heaven's Fall》: Level 100 Earth spell; it gives damage over a vast range by making countless meteorites appear. By determining the aim with an FPS point of view, the meteorites could be guided to a certain degree, and it was possible to increase the power in exchange for narrowing the range. Hard to use against small opponents, but extremely effective against gigantic monsters and large groups of opponents.
- 《Cross Blizzard》: Level 110 Wind and Water/Ice spell; Two tornadoes springs forth. All that touched them were frozen over, and on top of that, they were smashed to pieces due to the winds.
- 《Matoi Izuna》: A Wind and Light spell; by cladding a kamaitachi in lightning and firing that at the opponent, it would tear the opponent apart from the inside. While it would continue to bestow slip damage to the opponent for a fixed amount of time and paralyze them, it had the effect of bestowing large damage at the end. The "large damage" is a pure white explosion caused by a pillar of light that engulfs the opponent.
- 《Hercules Lance》: A level 120 Light Attribute spell. Creates a 5m spear of light.
- 《Naraku》: Level 130 Darkness spell; The effective range was touch--meaning it would only happen to the opponent it was touching. A magic spell that creates a minuscule black hole that forcibly imprisons the enemy in an airspace of darkness. The power is high and the effect is tremendous with only a 5% chance/probability it will Fumble and fail.
- 《White Nova》: Level 150 Fire and Light spell; The strongest magic spell that Diablo can use. On the tip of his staff, a pure white fireball about the size of a ping-pong ball is produced. The fireball then falls to the ground at a lax speed. The instant the fireball touches the ground, it will split open in a pure white flash with a thunderous roar--a disintegrating annihilation due to magic power should be repeatedly happening in the effect range of the attack. The effect range is a semi-circle that went about twenty-something meters forward from the caster's feet. Its power is tremendous enough to defeat a high-level monster in one hit. However, the weakness of such a powerful spell is the huge MP consumption along with how it took time until the spell is invoked (Diablo needed thirty-something seconds until the spell was invoked).
- 《Apocalypse Abyss》: A 《Forbidden Spell》. It established magical power points in thirteen spots and was something close to a 《Formation-type Magic》. Its power was high but with a long prep time which only makes it useful against an opponent that moves in a limited space. Within the set range, pillars of light rise up from the thirteen magical power points. The four classical chemical elements raged about and physical objects changed into dust entirely. Lightning ran around, magma blew about, and things that were frozen burst in an instant. A current of magical power was swirling about. The four classical chemical elements that were spouting out became a tornado tinged with lightning and rose to the heavens swallowing up the area in the set range and causing immense damage. This magic possesses the four elements of earth, water, fire, and wind. Against a being of the Darkness attribute, it has an extremely high effect.
- 《 Flight Magic》/《Adzet》: A magic which makes objects float. The caster can control how high, which direction and speed of the object. It has a limited effect time.
- 《Gravity Abyss》 A multiplex magic.
- 《Dark Arc Seek》: A maximum magic that makes a bow arc with limbs made of darkness.
- 《Black Hole Arrow》: A maximum magic that makes a black hole sphere.
- 《Air Block》: Creates an invisible barrier harder than concrete in the air.
- 《Lightning Sphere》: A three-meter sphere covered in purple lightning that slowly moves forward.
- 《Absolute Zero》: One of the Water Attribute's strongest magic. Any and all kinetic energy is completely and eternally lost. The target was limited to one person, and the spell won’t activate unless done at zero distance.
- 《Darkness Cannon》: A high ranking Darkness Attribute magic. It fires a jet black cannonball of condensed magical power.
- 《Grand Tornado》: A maximum magic. Makes a tornado.
- 《Earth Bounce》: An Earth Attribute magic. Creates an earth tremor. It does not affect whatever is within a 3-meter radius of the caster.
- 《Virus Cloud》: Poison magic. A level 110 Darkness and Wind Attribute magic. It makes a black cloud of poison and spreads it forward.
- 《Lightning Arrow》: A Light Attribute magic. The superior version of 《Bit Arrow》.
- 《Sonic Boom》
- 《Thunder Axe》
- 《Rust Burst》
- 《Chain Lightning》
- 《Rock Cannon》: A level 130 Earth Attribute magic.
- 《Lightning Meteor》
- 《Sylph Shield》
- 《Lightning Escalation》
- 《Press Shredder》: A level 110 Wind Attribute magic.
- 《Sonic Wave》: A Wind Attribute defense magic.
- 《Demon Squeeze》: A level 120 Darkness Attribute magic. The highest form of 《Dark Press》.
- 《Ice Age》
- 《Lightning Storm》: A high-level magic that possesses Light and Wind attributes.
- 《Enel Cannon》
- 《Sword Smite III》: A charge-in type of Martial Art. A part of a Martial Art series which includes 《Sword Smite》.
- 《Heat Sonic》: A Martial Art learned at level 80. A powerful technique that makes the edge go red hot, and cut eight times in an instant.
- 《Finger Blade》: A Martial Art that uses SP to give a bare hand the power of a dagger. It was able to cut through metal armor.
- 《Iron Wall》: A Martial Art that lets Diablo endure attacks with his SP. Using it, he defended against an attack that would have otherwise bisected his shoulder.
She is one of the two girls who summoned him to the other world. She married him in Volume 9
She is one of the two girls who summoned him to the other world. She married him in Volume 7
A Grasswalker he met at Zircon Tower city.
- Diablo considers cheese bread, a confectionery with a crispy surface with syrupy cheese and tomato inside, as the ultimate food.
- The Tonnerre Empereur (Thunder Emperor) is named from terms from Yukiya Murasaki's other series Altina the Sword Princess, Grand Tonnerre Quatre (Emperor's Thunder Quartet) one of the weapons of the first emperor of Belgaria L'Empereur Flamme (Flame's Emperor) which is now wielded by his descendant Altina.