Mash-Up Anime: Teenage Assassin Enrollment. - Chapter 8 - Harem!

After dying in the apocalypse, Su Jin was given a second chance as she was reborn into her former self just one month before the beginning of the end. Knowing that the world was about to fall apart, she started stockpiling everything she could. Her family started to think that she had gone crazy after her marriage and was ready to gang up to ruin the trashy husband. However, as the world suddenly changed around them, their air tickets and money were rendered useless and they now understood just how much foresight their beloved Su Jin had this whole time. As they continued to fight for survival, Su Jin’s husband scoured the city with several better-looking team members. One of them groaned while trudging ahead, This is the 212th time we’ve lost our way since the team leader began his search for his wife…

The 7-year-old little crybaby met 11-year-old big brother who ran away from home.
[This man became the protector of redemption in his life]

The 16-year-old little dragon fell in love with a 20-year-old big brother.
[It’s a pity that the big brother didn’t recognize him as the little crybaby]

The 23-year-old single father and 27-year-old chief executive meets again.
[This time the little crybaby and his big brother are finally together]

Fortunately we met through hundreds of millions of people, Thank God, for letting us break through many obstacles and get back together again, falling in love with you and being with you again is the greatest fortune in my life.

- Description from Novelupdates

Vahn was an atypical youth. Due to a rare mutation, his blood had the potential to target and attack ailments within the human body. Touted as a universal cure, people had elevated his status above the norm and given him the classification "Panacea". In the media, he was hailed as a great hero who would usher in a new era or human wellness. However, behind the scenes things weren't so bright. Being a unique individual, Vahn spent his entire youth locked up in a lab with various scientists and research teams using his body and blood to perform endless amounts of experiments. The only solace in his suffering was the various anime and manga made available to him between experiments. He often imagined himself as the protagonist in a world of his own, finally in control of his own destiny. For years he nurtured this desire, until at the age of 14 he died when an organization had tried to kidnap him from the lab...

Transported to a rural family in 1973, where eating required food stamps, dressing needed cloth tickets, stepping out asked for a letter of introduction, doing business was considered speculative profiteering, and securing a job demanded an urban household registration. She, a young girl from the countryside, faced an indifferent mother, a troublesome younger brother, and an elder sister who often had poor ideas. Life had become insufferable.Memories from her past life are mostly forgotten, yet the myriad of objects in her magical storage ring baffles her greatly.