The Magic Academy's Physicist - Chapter 19: Cleaning Up The Mess

Mark hatched out of an egg one day, reincarnated as a demon!His body was as strong as iron, instincts capable of noticing a silent fly multiple meters away. Eyesight sharp enough to see the small holes in an enemy’s clothing.Moreover, he also had a system.[Soul Devourer][Eat souls to grow stronger.][Mind-type Demonic Tricks have been derived out of your demonic bloodline!][Heart Input!][Input unsolicited thoughts in an enemy's heart and influence them!]Mark took a deep breath.How can he allow himself to live a mediocre life after being given this second chance?Now, he wanted it all!Women, wealth, power, status, and even eternal life!His ambition was set, his heart was on fire. A demon had been born.

We were a peaceful people living in harmony with nature in the vast lands of Lyréanor, but this peace was short-lived when our people were defeated by the dark elves, an ancient people even older than this world. It is said that they arrived in Lyréanor by boat and since their arrival, chaos has been unleashed. Proud of their obscure power, derived from dark rituals, they have raised gigantic armies of monsters whose name is synonymous with terror: ‘Obscurus’.They went on the rampage, and everywhere they went the grass didn't grow back, life died and disintegrated. Seven, there were seven. The seven dark elves known as the Lords of the Apocalypse. A single gesture from them was enough to strike us all down, a single gesture from one of them was enough to decimate us in blood and terror.And as I, Foster, contemplate the macabre scene before me, the bloodied and deformed bodies of my fellow elfes beings, and as death grips my soul, a strange sign appeared before me.[Ding... Activation of the world tree system]

A World of Warcraft hunter player inexplicably entered the world of Azeroth in his sleep. Turned into a high elf ranger, and at the same time inherited the title of Baron Cheap Daddy (Baron Blood Eagle) who died.

But the tragic original history that Blizzard bestowed upon the blood elves made his hair stand on end. He doesn’t want to become a heartbroken person and doesn’t want to die, so he can only struggle desperately to change the original history.

- Description from novelbuddy

Zero, a 35-year-old mercenary, after being betrayed by one of his teammates who told his enemy about him. He chooses suicide so that he can kill his enemy and his traitor teammate. After that, he was reincarnated into the world of magic, in the body of an 18-year-old teenager with the same name as him. However, his body does not have mana or the talent for magic. But with the help of the cultivation system, he has unrivaled power in the world and has a harem of beautiful wives.