The Great Mage Returns After 4000 Years (Web Novel KR) - Vol 2 Chapter 346

Matthew grew up in a decent family filled up with hopes, dreams and big heart, but living a shitty life which were suddenly demised with the unexpected turn with a mishap. With the new changes of his body, he finds new powers and wondering into new dimensions. This new enigmatic power is suddenly taking soul form his body and making him something beyond of his imaginations.... His tasks are unclear but he has to take soul of each demon he meets in his path... With his powers he has bigger responsibilities in each of the dimension which is beyond explanation…

In novels with a stud there is always a Senior Martial Brother like this:

In the early stages of the novel, his innate talent is high, his cultivation is good, his appearance is handsome, and he has an intelligent, cute younger Martial Sister as a fiancée.

In the middle stages of the novel, he is caught unprepared and defeated by a young disciple (the protagonist) in the sect who’s hardly remarkable at all. From then on, he falls from his godly altar and loses his brilliance. Even his young Martial Sister leaves him for someone else.

In the late stages of the novel, he continues to turn dark, going down the Demonic Path and becoming the major villainous boss. However, the protagonist still ruthlessly defeats him and his soul is eternally sealed.

Once Qin Mo opened his eyes, he discovered that he had become this Senior Martial Brother.

- Description from Novelupdates

Yuan Luoyi felt like she was a little hamster in a pit of snakes, with her family full of crazy villains, yet as the fake heiress she still focused on slacking off.

Dad was an arms dealer, Mom an ace assassin.

Eldest brother, business world’s killing god, with proxy syndrome.

Second brother, cold-blooded lawyer, zero moral sense.

Third brother, addicted to killing, born with antisocial personality.

Fourth brother, evil celebrity, who trained fans into believers.

Fifth brother, genius scholar, loves those pure white bones.

Yuan Luoyi didn’t know that because of her birth, the world gained five more brothers, not five more lunatics.

Those greedy villains also didn’t know, the one they wanted to kill was not an ordinary girl, but the most beloved little sister of five crazy bastard brothers.

The female lead has 99 lifetimes of memories, a system, harem darling + suspense, happy ending.

In the nation of Avrael, power is both a blessing and a curse. Sixteen-year-old Ayato Daath, a poor orphan, had always hoped to live unnoticed in the shadows of the city. But when he is forced to undergo The Rite of Manifestation, the ritual that determines one’s magical potential, his worst fear comes true—he is an Elite.Now torn from the only life he’s ever known, Ayato is thrust into a brutal world of magic, bloodshed, and treacherous politics. In a society where the strong prey on the weak, where rival factions scheme in the dark, and where a single misstep could mean death, Ayato must quickly learn one thing—adapt, or perish. And one thing Ayato already knows is that in Avrael, only the ruthless survive.