Heidi and the Lord - Chapter 61

The mighty void dragons are on the brink of extinction due to a strange condition. Their bodies have suddenly started rejecting their kind.

Due to that, Arad's mother dropped his egg into a forest where he could hatch safely, leaving him with a fragment of her consciousness and informing him of the condition of their race.

From that point, his goal became clear. To save their race by either mating a lot or finding a cure for their condition.

But, sadly, nothing is ever that easy. Arad is still practically a newborn and cannot tap into the terrifying might of his race, and his rarity makes him a prime target for mages and scholars seeking to study the dying race.

The doomsday fell upon the earth when a dragon coffin sealed under a snow mountain for ages shifted, and the civilization of gods and devils began. The whole universe turned into a fantastic new world where everyone could rise to the top through cultivation. A lucky young boy seized the opportunity, and started his journey to be an overlord in cultivation.

- Description from Novelupdates

The strongest Hero in history, Nakamoto Keisuke.

He was summoned to another world in the spring at the age of fifteen years old, and when he successfully defeated The Demon King, he was already thirty-two years old. He had finished his role in another world and returned to Japan, but the reality that had been waiting for him was, “Middle school graduate with seventeen years of blank period” label. He couldn’t find a decent job and had no choice but to spend his days working part-time.

Before such a Nakamoto, a beautiful girl who self-proclaimed had come to return the favor, appeared. “I’m the reward for Hero who had defeated Demon King”, said Angelica, a girl who came from another world that persistently tempted Nakamoto to make her his wife. Together with a high school girl who looks like Elsa, his beloved girl that he lost in another world, Nakamoto with his cheats skills got caught in a harem life.