Starting with Check-In Sacred Body of the Ancients - Chapter 30: Heavenly King Covers Earthly Tiger, Luoli is One Meter Five

A talented young man, Cyril Felling, just entered a prestigious academy of the great Empire, ready to begin his new life. Everything was supposed to go well.But suddenly he started seeing a strange woman trying to talk to him that no other human could see.Next, there was a student from the same grade saying she could see the future and that the world is in danger.And finally he discovered that his body was hiding some mysteries as well.All he wanted was to learn magic and prepare to fight demons in peace, yet he keeps encountering one weird situation after another.

He rose from abjection and achieved eternity in glory.
He embraced the prettiest beauties and killed the strongest opponents.
He was able to shift the clouds into rain and cover the sky with one hand.
He could overrun the entire world and go anywhere as he pleased.
He pacified wars and held the world in awe.
He was matchless in the world.
However, his hair turned white overnight for his beloved woman and he was on the verge of death.
He was surrounded by enemies who were trying to take his life.
He struggled his way to become mighty and fought for everything he cherished.
For this age, he was the only king of the Dark World.
His name was a byword for might.
As a man living in the world, his only ideal was to pursue brilliance.

- Description from Novelupdates

I, the protagonist, was just an ordinary NEET, but suddenly I was reincarnated as a tiny white snake in a fantasy world where legendary creatures and gods exist. Not only that, but I awakened in a cave as the offspring of a terrifying Medusa Serpent.Armed with only my human knowledge and my indomitable mental strength, I'm forced to use cunning tactics and rapidly evolving skills to survive against far stronger monsters and humans... So begins the survival story of a former shut-in with incredible willpower, living as one of the lowest-ranked beasts in a world of magic!ᆖMusic suddenly started playing in my head.I'd been waiting for this moment for so long.'Snakes! Assemble'....

A tree of 10,000 flowers, the world is the door.
The spells change a lot, but the hearts of the people are unchanged.

- Description from Uukanshu translation