(credit to @xyzdragon1234) 

I know I've finished the Ten Deady Sins oc's, however xyzdragon1234 was willing to create and his oc's into this story. 

Now these oc's are known as the Four Horsemen of the Apocalypse. They're the elite squad of Devil Hand, and the strongest wizard that are close to Y/N's level. 

Name: Ronin Ferrer

Age: 18

Alias: Azrael

Hair Color: Dark Purple

Eye Color: Black (Glows purple)

Gender: Male

Appearance: Also has an 8-pack and a muscular build

Personality: Despite him representing the horsemen of death he's actually a very friendly guy. He's nice, playful, competitive, and great to be around. However, When it comes to his enemies He's a totally different person. He's Serious, emotionless, and won't hesitate to do something drastic when it comes to saving both his friends and his sisters.

Guild Color Emblem: Black

Outfit: Black Hoodie with a black skintight sleeveless shirt underneath the hoodie, dark pants with purple neon lines and kneepads on them, black steeltoed boots, and black fingerless gloves.

Horsemen: Death

Magic: Shadow Monarch Magic, and Dark Demon Slayer Magic

Spells for Dark Demon Slayer Magic:  

1. Dark Demon Rage: The most basic attack of a Demon Slayer, which every Exorcist Mage knows how to use almost instantly, Rage is the Demon Slayer equivalent to a Dragon Slayer's Roar or a God Slayer's Bellow. The user gathers energy by inhaling and releasing a stream of darkness from their mouth, swatting their enemies with pure force. The power of Darkness' Demon Slayer mage depends on how much power is gathered and, overall, the strength of the user.

2. Dark Demon Slash: The user covers their extremities with the power of Darkness, then starts to strike the target with kicks and blows. That darkness has malleable and slashing properties: as such it can be divided into tiny tendrils to pierce their enemies. Darkness Demon Slash can be even more effectively imbued on weapons, greatly augmenting their offensive power and reach.

3. Dark Demon Hundred Knives: The user shapes a small amount of darkness in one of both hands into tiny blades, then hurls them away toward the enemies. The Hundred Knives comes from the fact that those molded weapons can be generated and molded in almost zero time and very little effort from the user, granting him a nigh-bottomless supply of throwing weapons. After they have hit their target, the dark projectiles vanish without leaving a trace. The user can also create and mold stronger knives to engage their opponent in close-quarter combat.

4. Dark Demon Spear of Judgment: basically a much stronger variant of Hundred Knives, the user molds darkness to form a long spear, generally more similar to a javelin, covered in shadows. The user then can throw it with much greater force than Hundred Knives toward its opponents, piercing effortlessly through hard materials and human flesh.

5. Dark Demons Laughter: The user gathers magic power in their hand creates medium-sized orbs of dark magic energy and releases them onto their target in a flurry.

6. Dark Demon Wings: The user creates bat wings made of darkness with which they can fly and they can even enlarge them and slap opponents

Dark Demon's Blackening: The extension of the wings spell where the user spreads their wings and unleashes a rain of black feathers that pierce through things.

7. Dark Demon Black Corridor: The user extends their shadows, spreading darkness over a large area. The shadow works like a black hole, swallowing up its target by pulling it down with the sheer force of gravity. Once pulled down, the targets are either kept imprisoned by a shadowy space, the same one a Darkness Devil's Slayer enters whenever he fuses with his own shadow, or the user can keep the gravity of the space as high as ever, crushing them under a sea of "dark matter". Objects and people in the Black Corridor can be pulled out at the user command, though they require an existing shadow to be drawn out. Black Corridor is among Darkness Devil's Slayer must versatile spells, as it can be used both to incapacitate or kill enemies or to summon objects at will. However, Black Corridor can be easily dispelled if the absorbed target "lights up" their shadow by burning a considerable amount of their magical power.

8. Dark Demon Night Slash: The user gathers great amounts of magic power in their hands and ends up creating a pitch-black scythe outlined in a violet aura. The scythe has the ability to harm only the intended target, phasing through any other obstacle, with a slash from it shaving more vitality than the basic spells.

9. Dark Demon Abyss Shield: The user gathers great amounts of magic power in their arm and shapes it into a shield that can absorb incoming spells and use them to maintain it. However, it cannot absorb light spells, only tries to block them.

10. Dark Demon Pandemonium Night: The user gathers great amounts of magic power in their body and releases an omnidirectional shadow mist whose true purpose isn't to obscure vision, rather, it is to project the worst memories and fears of those inside. The mist absorbs the negative emotions emanated by the affected targets and transmits them to the user in order to empower them. Alternatively, a user can use it on a lesser scale and have the shadow mist be absorbed by a target, with it becoming an evil version of themselves and being empowered by their most dark emotions.

11. Dark Demons Black Whirlpool: Extending their own arms, the user creates artificial gravity with their darkness to pull their enemies within their grasp, then attacking with higher momentum. The user can use spells also to grab objects far from him, like a crude form of telepathy. Black Whirlpool is excellent for keeping the user's opponent within their reach, but has a major weakness: if the enemies prepare an attack while they're grabbed, it becomes much more difficult for the user to defend themselves.

12. Dark Demon Gravity Sphere: After concentrating a great amount of darkness within the palm of one hand, the use form of a black ball and hurls toward the target. Due to the amount of darkness, the sphere possesses immense weight, crushing its opposition with its sheer mass before violently detonating. Gravity Spheres are difficult to launch in rapid succession, as it requires a lot of dark power to create one, but each spell could easily level an entire building or even more, depending on the user's power.

13. Abyssal Hell, Damned's Feast: The user begins by gathering huge amounts of magic power in their hands and claps them while saying the spell's name, unleashing a huge wave of darkness with numerous despaired faces with glowing eyes and fanged mouths that falls upon one or multiple targets, intending to devour them.

14. Abyssal Hell, Tartarus Breath: The user gathers huge amounts of magic power in their raised hands along with nearby shadows, ending up creating a tornado of shadows which the user throws at the opponent, sending them flying upwards into the air and crashing back down to the ground.

15. Abyssal Hell, Damnation Sentence: The user gathers huge amounts of magic power in their hands and claps them, with an iron maiden of shadows emerging open from beneath the target and trapping it inside, skewering them. It's the most costing spell of this magic in both magic power and concentration.

Demon Modes:

Demon Force: Demon Force is the final stage of the Demon Slayer Magic, the embodiment of the ultimate power that Demon Slayers may possess, though the exact conditions to invoke it vary from person to person. When entering the said form, the user's body fully transforms into the element the Demon Slayer has in their possession, by saturating the insides of their body and the outsides with an overdose of Magical Barrier Particles. Such form change grants them the enhancement of their physical traits, like strength and speed, and demonic abilities they have, improving their combat capability significantly. Demon Force greatly increases the damage done by standard Demon Slayer Magic attacks and grants the user access to more advanced, powerful attacks. It also drastically enhances the user's physical prowess, making them far stronger, more resistant, and faster, and boosts their demonic power, prompting it to violently become visible, taking on the shape of a demonic visage; When used at the fullest, the generated silhouette seems to gain corporeality, likely as a result of the immense amount of demonic power employed. As the Demon Slayer's entire body turns into their element, after activating Demon Force they are virtually immune to physical harm. They can allow any attack to simply pass through them or simply absorb the attack; it is essentially a boost in the demonic properties that Demon Slayer Magic provides to the user.

Overdrive: Similar to Edens Zero By allowing the user's Ether power to flow throughout their entire body, the user can acquire a massive boost to their capabilities as well as being able to achieve feats with their magic they normally wouldn't have been able to. Along with this increase in power, the user also takes on a new appearance similar to that of the machine; having three-dimensional lines surrounding their body and covering their skin.

Demon Force Overdrive: Combining the power of Demon Force and Overdrive the user is granted an even more powerful boost in their magic power that it even starts affecting the Ethernano around them.

Primal Force Hyperdrive: The Evolved version of Demon Force Hyperdrive, It's a form that only Ronin managed to achieve during years of Training by finding his inner Peace in his darkness and death. This not only affects the user's Ether lines by turning them into a rainbow color but also transforms them and turns them into their spirit creature from their slayer Magic.

Dark Demon King Mode: The user's darkness becomes so intense that it turns into powerful destruction energy capable of destroying anything and everything. The destructive energy is so intense that it even manifests in the enemy's biggest fear sending them into an intense state of fear and despair just by looking at Ronin. This mode is considered the pinnacle of Dark Demon Slayer Magic and he calls this darkness the "Darkness of Death".

Spells/Skills for Shadow Monarch Magic:

Stealth: The user is able to camouflage themselves and turn themselves completely invisible by erasing all traces of the user's presence. The user can control their aura and blend in with anything or anyone.

Telepathy: Ronin has the ability to hear and read the thoughts of his Shadows under his command. He is able to have conversations with his shadows as well as from long distances.

Shadow Armor Creation: By concentrating his powers around him he can generate jet-black and purple armor around his body, negating all magic that comes in contact with his armor.

Ruler's Authority: Ronin is able to move and control objects via telekinesis regardless of their weight.

Dragon's Fear: Ronin is able to release a mana-infused shout from his soul that drives anyone weaker than him into an intense state of despair and panic.

Shadow Extraction: Ronin is able to extract shadows from the corpses of his enemies and add them to his army.

Power Bestowal: Ronin can give portions of his magic to his friends, family, or allies to boost their strength.

Shadow Preservation: Ronin is able to preserve his shadows in storage and monitor them by receiving their senses. 

Monarch's Domain: Ronin is able to buff the strength of all of his active shadows by 50% in battle.

Shadow Exchange: Ronin is able to use shadow portals to travel vast distances he's been to in an instant.

Darkness Gaze: Ronin can launch a gaze of death or highly dark bloodlust at his opponents causing them to become intimidated which makes their survival instincts strongly activated by the fear of death. Anyone in Ronin's presence will experience deathly hallucinations of how they would die in their future against him often in several possible ways, either beheaded, mutilated eviscerated, and many other ways. 

Death Manipulation: As he is the Shadow Monarch's Successor, Ronin has the power to decide, determine, and manipulate the causes of death allowing them to choose and control, when, how, where, and why someone dies and even induce the circumstances/events that will lead the target appointed death. This is a power Ronin keeps hidden from everyone and only his sisters know of it Plus he rarely ever uses it. 

Soul Manipulation: One of his many secret powers, he can shape and manipulate the soul, the incorporeal and immortal essence of a living thing, souls are usually most obviously present in sentient beings.

Dark Soul Manipulation: With the powers of darkness, Ronin can create, shape, and manipulate souls of a darker, detrimental nature; that which damages, destroys, and consumes anything and everything they come across, representing the hazardous and destructive side of souls which in turn ignores most of the limitations and weaknesses of the normal soul. In essence, this is about solely controlling the negative powers of souls themselves.

Summons:

1. Igris

2. Tank

3. Iron

4. Tusk

5. Kaisel

6. Beru

7. Jima

8. Kamish

9. Greed

10. Bellion 

11. Kaya

12. Gojira

13. Karina 

14. Shadow Giants and 1,000,000 Shadow Soldiers