Ascendant Path of a Lustful Vampire - Chapter 18: Combat Magic (2)

One of the top expert killers, tired of endless assassinations and having survived a cruel and suppressed life, decided to escape the world’s strictest assassin organization.

It’s a affair between a loyal dog servant and his master.

- Description from Novelupdates

Eren Idril died as an old, decrepit, and piss-poor adventurer by the maws of a D-Rank monster. He had a lot of unfulfilled dreams and desires that couldn't see the light of the day after the light in his own eyes died down.

But fortunately for him and unfortunately for the world, that wasn't his end. Eren was somehow dived back in time when he was a mere teen, attending Lionheart Academy for adventurers.

When life gives him a second chance, Eren decides to exploit it to its fullest. Experience his vile deeds as he partakes in them without feeling the slightest bit of hesitation.

Chu Nan was just an ordinary student, but because of an accident, he obtained the data collection, analysis and processing ability equivalent to the most advanced optical brain.