MTL - The Manga of Ten Thousand Realms - Chapter 57

Earth is submerged in Chaos.Mutated Beasts roam the globe and Gates that lead to Otherworldly Dungeons appear everyday, bringing great dangers to humanity.However, the Awakened emerged, giving a chance for Humanity to survive.Amidst a vulnerable and crumbling society, a powerless and bullied young man begins to hear the voice of a malicious entity inside of his head...“Do you desire power, Noah?”Follow Noah as he gives up his humanity and sanity to achieve the power that others could only dream to have, overturning the order of the world and annihilating anyone that dares to cross his path!Watch as Noah dominate this world, the galaxy, and then the universe!

I was reincarnated into another world, and I’ve brought the Horadric Cube from Diablo II with me.
Being a knight is cool and all, but being a wizard is pretty neat as well.
So, which one will it be?

- Description from Novelupdates

In a world intertwining magic, knights, and burgeoning technology, young Leonard grapples with memories of a past life in the modern world after waking up reborn in this new, tumultuous reality. Separated from his family amidst a devastating conflict, Leonard's life takes a precarious turn when he is taken under the wing of Alfonso, a reclusive and somewhat deranged wizard. Under Alfonso's tutelage and the rigorous demands of a daily task panel that rewards him for mundane chores with experience points, Leonard finds himself thrust into a harsh survival regime, far removed from his previous life's comforts. His daily life oscillates between mastering arcane spells, learning the delicate art of Earth Ring meditation, and handling the meager sustenance at the prison-like estate where he and Alfonso reside.As Leonard's skills grow, so too does his awareness of the wider conflicts that plague this world, blend of industrial revolution-era technology and dark magical forces. The task panel becomes a strange companion, guiding him through tasks that blend the mundane with the magical, pushing him to grow stronger. Amidst the backdrop of this grim reality. The complex interplay of power, survival, and the echoes of his former life drives Leonard to not only master his new abilities but to unravel the mysteries of this world and perhaps find a way back to his family, despite the cold indifference of his master. Each experience point earned and each new ring formed in his meditation brings him closer to understanding this world's brutal truths and his own place within it.