Maoyuu Maou Yuusha - Volume 2 Chapter 6, “Your Lap feels good, Hero.”

Yamagata Tatsumi and his family were traveling in their car when a wild truck smashed into their car. But wait! The MC wasn’t dead yet, his entire family was though. With his entire family dead and relatives abandoning him, the only one remaining by his side was his pet cockatiel. For a year he lived only with his pet, who had been with him since childhood. But finally, her lifespan reached its end and she died in his arms.

It is the story of a young man who died and was reborn as a level 1 skeleton soldier in an underground world. Follow our protagonist as he struggles to survive in a foreign, RPG-like setting surrounded by danger and monsters. Watch as he levels up and overcomes all obstacles through sheer perseverance and wit, rising to prominence

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