I'm the Owner of the Pokémon Day Care In the World of Pokémon - Chapter 1366: Decidueye vs. Eelektross

Yuki, a high school junior, dies heroically saving a stranger and is reincarnated in a fantasy world, where he discovers an extraordinary and unrivaled power.

[You have entered the dungeon at Gwachun Station’s 1st Exit.] When former high school student Kang Woojin finds himself returned back to Earth after being forcibly summoned to a foreign planet for 20 years, he soon finds that Earth is not the same, normal place as he once remembered it to be.

The Master of the Tai Yi Sect, Patriarch Xu Yi shattered the void, causing the entire sect to travel through to the interstellar era.

On the deserted planet, the disciples discover a new world:

The eldest senior brother, who specialized in forging, fell in love with mech building. The second senior brother found that alchemy could also be manufactured on an assembly line; The third senior brother fell in love with live broadcasting and was addicted to the Internet; The old Master Xu Yi cracked his whip and urged the disciples, ‘This world is so rich in spiritual energy, how dare you not cultivate properly?’

In the Immortal Cultivation Realm, Junior Sister Sa Sa, who had no spiritual root and powerful spiritual sea, was finally no longer distressed by her inability to cultivate: ‘Mech’s are really powerful!’
Double standard — Xu Yi: … Study it. Isn’t it just mechs, Sa Sa should have one too.

A little bumpkin from a deserted star came to the Federation’s First Academy.

Sa Sa, ‘Wow, the internet is awesome! Mech’s are awesome! Technology is awesome!’
‘You don’t need to cultivate to become strong in the interstellar world, I really love love love it.’

Students from prominent and powerful backgrounds scoffed, ‘Where did the bumpkin come from? Is there something wrong with the admissions system?’
They had no idea that the anchor who exploded onto the internet had a great relationship with the little bumpkin.

Sa Sa: ‘Third Senior Brother is secretly on the internet again!’

The elixir that the little bumpkin usually took and hard to find, the spirit sea boosting pills with no side effects, was actually worth a thousand bucks?

Sa Sa, ‘Second Senior Brother makes the most delicious sweet pills!’

The mech that the little bumpkin casually pulled out was actually the upgraded version of the mech that everyone was fighting over?!

Sa Sa, ‘Eldest Senior Brother will definitely save the best for me!’

The whole planet was abuzz: ‘What kind of divine institution was Tai Yi? How do I get in? Waiting online for a reply!’

- Description from Novelupdates

At the beginning of the 21st century, twelve reincarnations shattered the void and returned to their hometown.

They preach the world and reopen the space of reincarnation.

Then……

“The Republic of East Asia announced that it will fully implement a five-year spell casting and twelve-year simulation mage training policy.”

“The Republic of East Asia has announced a new change in the marriage law, making it legal to marry someone you call upon after meeting the adulthood conditions of your respective race.”

“The Republic of East Asia announced that the East China Military Region No. 1 Mobile Armor Brigade was established, and the special humanoid mecha “Gundam” officially joined the campaign.”

“Congratulations from the United Kingdom on this, the upper hero Arturia Pendragon will visit Shanghai next month”

“In the far east of Japan, the ignition of the wave engine failed, or seek energy assistance from the East Asian Republic.”

“Space cracks have been discovered in the Chernobyl region, alien creatures have ravaged the Chernobyl region, and the Russian Defense Forces have entered the battle.”

Four years after twelve reincarnators changed the world, Li Ping entered his own battlefield for the first time.

PS: Although the introduction is like this… but in fact it is written about two thorns + machine battle + movie + mythical stew…

- Description from novelbuddy