MTL - Ninth in The World - v3 Chapter 1335 I can find

The mountain village boy accidentally got the fairy gourd, and he rose step by step to cultivate immortality and longevity.

Ripe elixir, mortal flow.

- Description from novelbuddy

Eren Idril died as an old, decrepit, and piss-poor adventurer by the maws of a D-Rank monster. He had a lot of unfulfilled dreams and desires that couldn't see the light of the day after the light in his own eyes died down.

But fortunately for him and unfortunately for the world, that wasn't his end. Eren was somehow dived back in time when he was a mere teen, attending Lionheart Academy for adventurers.

When life gives him a second chance, Eren decides to exploit it to its fullest. Experience his vile deeds as he partakes in them without feeling the slightest bit of hesitation.

This is the story of Ryo, who was reincarnated in the world of swords and magic.It is a story of the royal road to survive using the magic of water attribute.What is magic? What is swordsmanship?How does it relate to the laws of physics that we know?Or what is politics? What is a nation?Why are there many 『kingdoms』 in reincarnation stories? Will republics not work?Can it be written …?Since it is a water-based magician, so it shall start with 『Hydrogen bond』!

Six months ago, tens of thousands of black phantom towers appeared all over the world, floating above the cities. Chemists, physicists, religious people… all of them could do nothing.