Start in DxD as Motohama: Leveling Up in Another World - Chapter 30: A new resolution, the same goal

The dawn era after the end of the half century has gradually rebuilt the order, abandoned civilization, and is full of undivided violence and desire.
The noble and powerful pioneers are in charge of the city, and the evil and mad plagues are in the wilderness.
Pure human beings who cannot mutate are the weakest, dominated by the rulers of the pioneers, and are not as good as animals in the wilderness.
A purely humanized young man with a worldly experience has quietly entered the WTO, holding a three-foot long knife and a long-distance desire to boil in the world of purgatory. From the nameless name to the sorrow of the Supreme Court, the name of the black ride is resounding!

- Description from Uukanshu (translated)

Ahjung is preparing to fake a marriage with her gay childhood friend Jigyung in order to earn 500,000 dollars. She was an unknown actress at the age of 33 and was expecting her parents to strongly disagree but wait. Why is no one stopping us? Why is this so easy?

And as the marriage was about to succeed.

“Brother, are you crazy?”

A man crashed in and shouted.

“I AM AGAINST THIS MARRIAGE!”

[Congratulations! You’ve unlocked the Dimensional Motel System.][First Mission: A runaway princess—hailed as the most beautiful in the land is being hunted by her step-mother. She was originally headed to the dwarves’ cottage, but the System has rerouted her to your motel instead.][Protect her. Win her trust. And if you manage to woe her, you’ll earn her Affection Points.][Bonus Mission: Sleep with her evil stepmother to unlock more reward]'What kind of weird mission is this? And why does this story sound way too familiar?'

For ten long years, Adam was a prisoner within his own body, paralyzed and helpless, silently observing a world he couldn't interact with. As his life finally ebbed away, connected to hospital machines, his last conscious thought wasn't one of peace, but a desperate, burning wish hurled into the void: If I get a second chance, let me be the strongest.The universe, in its mysterious ways, answered. Adam was reborn, not into light, but into an infinite, suffocating darkness. Yet, within this void, he discovered an astonishing truth: he possessed unimaginable power. Reality itself seemed to bend to his mere thought; he could conjure wonders or horrors with a whim. He was, by all measures, the most powerful entity imaginable. But this godlike power came with a cruel twist – he was utterly trapped, unable to escape the encompassing darkness.His prison, he soon grasped, wasn't empty space. It was the consciousness of another being. He was an unseen passenger, a silent god locked within the mind and soul of Eric, the unassuming Third Prince of a kingdom unknown to Adam. Eric, frail and seemingly ordinary, was completely unaware of the cosmic powerhouse dwelling within him.Adam's initial goal was simple: escape or seize control. But a chilling revelation halted his plans – his existence was inexplicably tethered to the prince's fragile life. If Eric died, Adam's own newfound power, perhaps even his very being, might shatter. A reluctant protector was born from a desperate prisoner.Now, Adam walks a razor's edge. He subtly guides and shields his unwitting vessel, Eric, from the dangers of court intrigue and hidden enemies, intervening with earth-shattering displays of power only when Eric faces certain death. These brief, terrifying moments where the “weak” prince unleashes godly might leave the world baffled and fearful, whispering legends of the prince's hidden potential.To navigate this precarious existence and perhaps forge a path to his own freedom or dominance, Adam devises a unique tool: a 'System' granted to Eric. Is it a gift to empower his host, a means to strengthen the vessel for eventual takeover, or a dangerous gamble with unforeseen consequences?As Adam fights unseen battles, protecting Eric while plotting his own endgame, questions linger. Can he ever break free? Will Eric discover the terrifying truth of his inner 'guest'? And what will happen when the world realizes that the power shaking kingdoms doesn't belong to the prince, but to the ancient, godlike entity trapped inside him? His journey is one of immense power bound by frustrating confinement, a hidden war fought within a single soul, where the fate of a prince and the ambition of a captive god hang in the balance.