MTL - Mystery Descends: My Exchanges Are Not Equal - Chapter 42 , Obsession upgrade! Fighting power skyrockets!

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

Lucian Bowcott only wanted a quiet life. He met up with old friends, made a wish, and died after one drink.Now, he awakens inside a coffin—summoned by the Half-Dead Queen of Atraeum and surrounded by restless souls.Armed with the Death Grimoire, Lucian must embalm corpses, repair brittle bones, and help the dead find peace… before something ancient finds him.As his powers grow, so do the whispers in the dark. If he wants to survive, Lucian must unravel the Queen’s grief, discover why a mortician hasn’t been summoned in over a century, and confront the entities haunting his every step.A/N: It doesn't deal with dungeons, Lucian's system is a magical book, and he slowly unlocks powers to help him with his next assignment. He travels to different places around Atraeum, and in the future, another kingdom.This is a character-driven gothic isekai about an introvert learning that sometimes, peace is more than just embalming a body and preparing it for a funeral. He's more of an undead therapist now

Jack Smith’s life ended rather abruptly. Spinning out on ice while driving a truck was not the most magnificent method to depart this earth. A mediocre man he had led an ordinary life until his death. Now with a second chance at life, he decided that this time he would be exceptional. This time he would finally live up to his name. After all, a jack of all trades is a master of none but ultimately better than one.Armed with a system and determination to do his best he sets out like any other reincarnated soul in another world to find his place and achieve great things. There is just one small problem with getting started in this endeavour . . . he is yet to be born!Welcome to a progression fantasy with a twist. What might you be able to achieve if your race to the top began before your body had even been born?Join our hero as he masters the language, magics and skills of the Compass Kingdoms but his first great challenge will be learning to walk once more. . . . .Warning 1: Be prepared for the MC to spend an entire book's worth of words and time as an infant but hopefully you will enjoy it nevertheless.Warning 2: Grandfather is legally abusive to MC for a couple of chapters but he is removed from that situation around chapter 30. To be edited out some time in the future.

There is no master god, no system, no exchange, and some are just source codes that are fused in the mind to open up the world, not to be forced or suppressed, but to constantly go through in order to become powerful Look at my infinitely powerful source code …

- Description from uukanshu