The Detective is Already Dead - Chapter 12 - 2.4

Earth Online – a virtual MMORPG that takes place in the future year of 2190 – a game that everyone will bet their futures on. Set in a map that is ten times the size of real-world Earth, players battle for supremacy in the first game to feature personal adventure, territory construction, and grand warfare. For every death you experience in the game, your level would drop back to zero. Ouyang Shuo, an above average player, suffered the ultimate betrayal. For merely a piece of equipment, his sworn brother betrayed and backstabbed him. This time, after he reincarnated in the game, Ouyang Shuo swore to exact vengeance.

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

Xia Lian, a 21st century military doctor died in an explosion and found herself transmigrated to the body a 12 year girl. Her mother died and her father abandoned her and her little brother for another woman.

The empire has turned into the land of the undead due to a spell gone wrong. God summoned heroes from countless worlds to purify the empire and plant new hope. Lee Shin Woo, an ordinary earthling, was also summoned. As an undead, that is.