The war between humans, monsters and demons had been going on for millennia. Monster raids caused mass death tolls, and caused a large amount of humans to get mad. These humans to got mad were the first to unlock abilities that the Humans called 'Magic Sets'. Anyone of any background could have a Magic Set, but, of course, Nobles were stronger. They were able to buy potions and other items to increase their magical strength, and how long they could cast spells for, also known as Magical Stamina.
This used up "マナ", which the humans translated as "mana". The term 'MP' came about as a shortened term for 'Mana Points'. The humans came to learn about Mana Points by reading journals written from a period in time where intelligent beasts roamed the land.
They had left their journals behind, and some humans had began to translate the text they had written, leaving them with the knowledge of their abilities, what they used, and why iit existed.
Mana is a by-product of the Planet Core, which, you guessed it, is the Core of a Planet. It naturally created this on accident, and it leaks to the surface, only after it becomes weaker due to needing to be sent further away from the source. This is the reason Dungeon Monsters are more dangerous than "Overworld Monsters", as they are known as.
The humans were happy with their abilities. They didn't want to risk their lives just for a bit of extra magic usage. That was, of course, before some human found an entrance in the ground that led downwards. A group of humans followed the staircase downwards, and were assaulted by a group of skeletons. The first interaction between humans and monsters was skeletons.
Once demons had realised that a staircase from the dungeon to the surface had been formed, they had some of their finest experts build a set of portals which led from their own empire up to the surface. They wanted everything they could get their demonic hands on. They had the portals built, and they activated it. The portal flickered to life on both sides, as a group of demons walked through the portal, to find the portal had been built in a minor village. They went on a rampage, almost every demon entering that portal, each one thirsty for blood.
One human was capable of standing up to them. The hero of legend, foretold in a prophecy spoken by the earliest form of the Holy Church. He had the ability to slay darkness, although that is not what his ability line was. His ability line was a customised one, which he titled 'Purity'. His ability line amounted to one singular sentence.
His ability allowed him to slay any being with darkness in their heart.
This is what made him a hero. His unique line allowed him to slay monsters, for they all had evil hearts. No compassion. He was, however, killed in the final battle against the Lord of Shadows. They both died at the other's blade. The hero let out a smile, as his body became limp, falling to the floor, as the Lord of Shadows dissipated.
The demonic prophecies foretold of a day when the New Lord of Shadows would rise and guide them to victory against the humans. They lived by this belief for many thousands of years.
Then, we reach the present. The New Shadow Lord is fighting a human wearing a suit of armour. It's almost like he's suicidal.
Of course, the being The New Shadow Lord is fighting against isn't a human. It's Aaron Stone, The Holy Black Skelengelis.
Aaron was rapidly slashing at the Shadow Lord with his scythe, cutting through him, but the Shadow Lord was able to regenerate almost instantly, meaning his scythe swings did nothing.
Aaron lifted up his armoured hand, as a white blast began to form in the center of it.
"Skelengelica!"
A white beam shot out of his hand, faster than anything Aaron has unleashed to date, and it just barely hit the shoulder of the demon, which did cause a temporary hole to form, but it was filled in around five seconds later.
Aaron then remembered his insta-kill attack using Boundless Telekinesis, but the Shadow Lord's eyes glowed a pure red colour.
[Instant-Kill Move 'Telekinetic Psychobreak' has been disabled.]
So that's what that move was called.
Aaron lifted his hand into the air, as a large purple field surrounded himself, covering the entire throne room, as he yelled out some words.
"I harness the harness! Gravity Field!"
The Shadow Lord suddenly felt slower. He shouldn't, because he is made out of shadows, but it did, and he wasn't able to figure out why.
Aaron lifted up his hand, and prepared to unleash a Skelengelica attack, bit he was tackled to the ground from behind. It turns out that the Demon Lord's Assistant had never left the room, and due to Aaron's light weight, he was able to be pulled down, and he couldn't get up, because of this Assistant. This wasn't good.
He lifted up his hand, and prepared slice at the demon with his scythe, but as he was about to bring it down, the Shadow Lord grabbed it, and lifted Aaron along with the assistant up.
The Demon Lord is the Shadow Lord, so either the Shadow Lord's Assistant or Demon Lord's Assistant would be a fitting term.
Aaron made his scythe disappear, causing himself and the assistant to fall into the ground. The force from the slam was enough to let Aaron pry his body from the Assistant, and jump away. He made his scythe re-appear, as it becane coated in a purple light, which became almost invisible due to it blending in with the ground.
Aaron rushed towards the Demon Lord, as he swung his scythe, and in the middle of flinging it, let go, and charged in with his sword.
His spinning scythe caught the Demon Lord off-guard, and it tapped him on the shoulder. This effect pulled down the Demon Lord even more than before, causing an even more visible lack of movement. Aaron rushed forward, and stabbed with his sword, thinking he did something cool, but the Demon Lord smiled, as a chuckle arose from his chest.
"You IDIOT. You can't stab a shadow. It's immaterial."