MTL - Beauty and the Bodyguard - Chapter 13 Cave adventure (below)

The Spirit Network, known as【Deep Sea】 connected five continents as human civilization surged forward; yet, they were oblivious to the impending eternal night. With the Extraordinary Awakening, the edifice was about to collapse. Flesh is weak and pitiful, how could one ascend? The story began when Gu Shen, an ordinary youth, received a ruler that bore the truth. He peeled back the corner of this extraordinary world, becoming the largest moth among the thousands that dashed into the flames. If winter is coming, I will climb against the steps, overturn the thrones of kings, shatter the crowns of falsehood, destroy the scepters of injustice. I will become humanity's last, Bright Barrier.

He lived from BC to the Middle Ages, from the Renaissance to the Industrial Revolution, and from Cyberpunk to the Interstellar Age. He has been a king and a prophet, a knight and a nobleman, a versatile artist, a genius inventor…
This is a four-thousand-year human epic——
“To us four thousand years from now:
“Is the world at peace? Is famine extinct? Can people touch the stars? How long is the human lifespan? How far is the boundary of the earth? Human…do you remember us?”
——Excavated from Earth Age Tenth Century BC, Solomon Prayer Book.

- Description from novelbuddy

Six years ago, he disappeared silently! After six years, he becomes the unparalleled "God of War" and returns with glory, only to find that he has a daughter whom he never knew of. Looking at his wife and his daughter, he says, "In this lifetime, I'll bring you the greatest honor and glory!”

Eli was transmigrated to a world of magic and became immortal.

He had endless life and could never die.

“Huh? I’m talentless? Then, I’ll just train for as long as I need, even if it takes 1000 years. That should be enough for me to become strong.”

“The skill is hard to learn? Then, I’ll take a few dozens of years to research it. There’s no way it’s that hard, right?”

“What? I can sacrifice my life force to gain spirit power? That’s a bargain!”

“The enemy is here? Hell, I’ll just hide for 10000 years. Let’s see if he can outlive me. I’ll come out once he’s dead.”

This is the story of an immortal who first struggled to live in the world of magic until he became strong enough to slaughter endless worlds.