Reborn; A Slave to the World - Chapter 82: Warp Key

I originally thought this was a world like an ordinary urban novel…Drawing comics by myself, traveling is pretty good.
But tell me, what happened to this magician called “Emiya Kiritsugu” who jumped on my face?
Who changed the settings?
Currently involved in the content of “F/Z”, “F/SN”, “Fantasy Carnival”, “The Emiya’s Meal”, “The Holy Grail of the Imperial Capital”, “FLA”, “Elmello II Event Book”, “FGO”, “FE”, etc.
Others related to “JOJO’s Bizarre Adventure”, “Rebellious Lelouch”, “Persona 5”, “Attack on Giant”, “Death”
“FGO”, “FE Series”, “FA”, “FSF”, “Cangyin”, “Magical Girl Illya” will be involved next…

- Description from novelbuddy

In the year of 2013, the tide of zombies outbreak exploded in everyone homeland, humanity launches a large-scale battle in the endless nights awaiting for the arrival of the dawn.

The end is approaching, is there going to be a way out for them?

Their faiths were shattered into pieces and buried in ashes in the raging fire.

But within the blazing fire, a newborn hope arise once again.

- Description from Novelupdates

Enemies to lovers? ✔️Villainous and possessive ML?✔️Fiery spirited FL?✔️Dark Romance?✔️Excerpt:“Wife?” Lady Karina repeated, almost shouting as if she'd misheard him.“I would not marry you even if you were the last man in this world,” she remarked with sweet venom, a poison Van Merikh would gladly drink. “You are a murderer and a thief. I do not want you!”“But I want you,” Van Merikh stated firmly, his dual-coloured gaze leaving no room for argument. “And that is where this conversation shall end, Lady.”Van Merikh threw open the door and practically dragged her to the base of the stairs that led to the upper floors. When she refused to mount the steps, he easily lifted her onto the first step and spanked her soundly on the bottom.“Go to your chambers,” he ordered softly.“This is not over,” Lady Karina growled. “I will fight you with the last breath in my body against this…this madness.”“Go, or you shall feel my hand on your backside again.”**************Magic as the world of Ethuaria knew it came from the distinct markings specific to each bloodline and nation that a person may or may have not been born with.It would appear at birth on different parts of the child's body, bringing about unique abilities passed down in their bloodline from mother to child.And for eighteen-year-old Lady Karina Hyacinth Reinhardt, life had always been one of comfort and peace with the secret abilities of her bloodline.As the beloved, yet sheltered, heiress of Moonveil Keep on the borders of the Kingdom of Caelthywn, she spent her days managing her father's lands and overseeing the affairs of their people, never knowing true hardship.War as she knew it was a distant nightmare that would never touch her.That was until Orpheus Van Merikh, the most feared warlord across the lands, invaded her home and seized it for his claims.Known as the devil himself, Van Merikh does not simply claim Moonveil for its riches, but also for the rumoured beasts that the Reinhardt bloodline conceals from the world.He will stop at nothing to have them.Thrown into captivity, Lady Karina expects cruelty, and Van Merikh, being the brute that he is, proves her expectations to be true.As a calculating and disciplined man who kills without hesitation yet protects what he claims, when one of his knights speaks ill of her, Orpheus cuts him down without hesitation.Lady Karina is his prize, but he would not allow others to dishonour her.However, she is not as obedient as one might think. Thus, determined to reclaim her freedom, Lady Karina refuses to cower as she challenges the enemy at every opportunity.Her defiance amuses Van Merikh, who spares her life due to her efficiencies in managing Moonveil Keep.Along the way, as they battle to find common ground, Van Merikh faces a rebellion among his own knights, who reject his growing attachment to her.They would have her dead before she warmed his bed.And oddly enough, Lady Karina finds herself charmed by the other merciful half of Van Merikh, but when her father returns to Moonveil at her request, much changes henceforth.Conspiracies arise and she soon slips out of Van Merikh's hold when he leaves for yet another conquest away from Moonveil.All hell would break loose when the beast from the depths would return upon Moonveil only to find his angel is gone.

Long Fei, a cross-timer and doujin, is an otaku who traveled to another world. In the original world, he was an otaku fan of Gundam and military science fiction.

He died in an accident and was reincarnated into another world. The Gundam works he had read before his death and the techniques in various military novels could be brought to another world.

How would he use the Gundam that Long Fei created? What waves can be caused in this different world?