Avatar: Mage of All Elements - Chapter 14

After dying prematurely from an incurable disease, Yuka Hikano finds himself in a mysterious realm filled with endless doors, each concealing divine gifts from powerful deities. He is not alone—others who have met the same fate of death stand beside him, unaware of the trials that await.They are put through various tests and eventually transmigrated into different worlds. But these worlds are nothing like the Earth they once knew.For Yuka, however, this apocalyptic world feels eerily familiar. It is a realm of endless war, devastation, and chaos—a world he once played in a game. Certainly not the kind of place one would wish to be reborn into.From infancy to adulthood, he must gather strength, knowledge, and allies to survive the horrors that lurk ahead. But when he awakens a system granting him a power beyond imagination, he soon realizes that blessings can also be curses.[You have gained Infinite Mana.]Infinite Mana...?What could possibly go wrong?

[Across the Stunning Beast Princess: Phoenix Against the World]

She, First Princess residence’s only legal daughter, yet known as a waste throughout the whole country!

When her cold eyes opened, she is the 21st Century’s most dangerous genius assassin!

When the sickly young miss exposes an edge, she is absolutely brilliant, and countless men and women in the world greatly admire her……

He is the absolute king of the night, cold blooded and ruthless. In troubled times, he by chance meets her, a zither and flute ensemble, since then in heaven and earth, life and death go hand in hand.

- Description from Novelupdates

With a marriage contract forcefully done, he married her, and all she could do was comply, and resent him deeply for that and for all the following misunderstandings they faced.
However, it was already too late when she understood she actually loved him.

A mortal teenager strayed into the immortal way because of an accident, struggling on the road of seeking immortality.

Immortal Road is difficult to climb to the sky, in the face of numerous obstacles, his desire to seek the truth is still unabated.

Looking back again, the green mountains are still there, so the old is boneless.

- Description from novelbuddy