MTL - The Top Beast Master Reborn In the End of the World - Chapter 15 [Seeking collection, seeking branches ^_^]

A 30-year-old NEET is reincarnated into the body of an otaku that choked to death on instant noodles. As he comes to grips with his new life, he realizes that this world is subtly different from Earth. The denizens of this world are far better looking, and this new world also possesses futuristic technology as well as mysterious Yin Yang masters!

After reincarnating, he realized that he was endowed with a miraculous game-like system, which enables him to increase his own stats and transcend the limits of the human body. This system even has a game-breaking ability to save and load in real life!

In this new world that’s akin to a 2-D game, he just wants to enjoy life and head for a glorious future… However, he is quickly embroiled in a complex plot. Can he unlock his true potential and utilize his system to break the shackles that confine him and discover the truth about his previous body’s circumstances?

- Description from novelupdates

Elias' world was destroyed right in front of his eyes. Only after his transmigration did he learn that there was nothing natural about its destruction.“Mother, I passed my Practical Exams! I was so lucky to get a weak world like Earth for my practicals! It only took a few months!”The person who destroyed his world was the eldest son of the family he was transmigrated to, the Ashborns.He could never forget his sister's cries when she suffered and eventually died from the virus that wreaked havoc in his world. And here he was, the person responsible, laughing.Elias wanted to repay the favor. He wanted to bring absolute ruination to these people. And for that, he had to play by their rules. He had to become the Architect of an Apocalypse…

“Married rich for three years with no child born. Just when she was finally cured of infertility and ready to give him a child, he brought home his pregnant mistress in high profile.

“”Get lost if you can’t get knocked up. Or do you want my son to be the last of the Mo family?”” her mother-in-law viciously cursed.

Her husband grimly shoved a divorce agreement upon her face, “”I’ve signed. Leave when you are ready.””
It was heard later that two men went physical in the city plaze of Ye City to win back the wife, with the two babies at the side fighting fiercely for their mom!”

- Description from Novelupdates

To be exact, the female lead is an “older sister” type, amid many beauties and handsome guys, she's no white lotus.Also, it's said that the name of this book is the same as a brand of sheep's milk powder.