MTL - Heroes of the Invincible Undead - Chapter 2879 prophecy ace

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

Matthew, a 25-year-old otaku, never imagined his obsession with fantasy worlds would turn into reality—until a fatal gas leak ended his life and transported him to another world.But this wasn’t the second chance he hoped for. Born as the illegitimate son of an affair, his very existence was a stain on his family’s honor, and his father relentlessly sought to kill him.Yet Matthew, now Claude, survived, again and again, driven by an unyielding will to live.Until one day he discovered his power darkness. Feared and reviled in this world, dark mages were hunted and burned alive.Knowing his gift could become his downfall, he trained in secret under Theo, his true father.When he turned sixteen, he, his mother, Dalia, and Theo planned their escape from the small town.But their attempt was thwarted by knights and clerics from the Promised Land.Though he narrowly escaped with his life, the cost was high—his family’s safety shattered.Wounded and desperate, Matthew fled to the fabled Elysian Plains, the last hope for those like him.Just as he reached the border of the Elysian Plains at eighteen, an ambush left both him and his mother gravely injured.Collapsing on the sacred ground, he heard a voice echo in his mind:[Welcome to the Elysium of Darkness System, Lord of Calamity.][Your first quest is available!][Increase the number of dwellers in the Elysium using your seeds and blood! Spread your legacy by making demons and witches bear your children!]

Polygamy is abolished.

We don’t have to force ourselves to live together anymore…

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.