MTL - Maze Survival: Only I Can See Hints - Chapter 428 +5 Divine Fire Fragment, Peerless Swordsman

For Marco, Lucas is his meek little brother. For the rest of the world, he is the menacing Ghost of Vermil.“Angels endow blessings. Demons sow curses.” A hundred years ago, angels and demons descended on earth. It is said they are still here.Annointed with potent holy power, Marco is set to join the Kingdom's Holy Army to fight off the demonic legion. But before that, he must confront the trail of blood and ash that points to Lucas's involvement with the dark side.As mysteries unfold and loyalties fracture, Marco is faced with the question: where does holiness end and damnation begin? If all lines are blurred and the fate of humanity is at stake, will he have enough resolve to strike down the brother he once swore to protect?

There are a total of seven sins, and a revelation is made to a young man named Alex that he is destined to become a demon lord, more especially a demon lord of sin called LUST.

It's not like he can change that and because he always knew something about himself was different—not in a physical sense, well, maybe a little—and not in a mental sense—but rather because he is thrown into a demonic war that compels him to accept his new reality.

He was only aware of a difference in himself. Relating to him and the ladies who are drawn to him... Well, it was more or less like he was a magnet in front of all the girls, and all the girls were drawn to him like a metal.

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates

The fiancée has betrayed, but how could she know that the man she looked down upon was in fact a prodigy with healing and martial prowess!