Devil Slave (Satan system) - Chapter 1 To Be Like Master...

A 30-year-old NEET is reincarnated into the body of an otaku that choked to death on instant noodles. As he comes to grips with his new life, he realizes that this world is subtly different from Earth. The denizens of this world are far better looking, and this new world also possesses futuristic technology as well as mysterious Yin Yang masters!

“From today onwards you are no longer my son. Get out” Being born into a noble family that is aiming to become the ‘strongest’, at his aptitude ceremony held on his 12th birthday it was discovered that Igni could only use fireballs. Igni who can only use beginner level magic was kicked out of his house.

With no where to go and without much magical ability, Igni is scraping by through life. However, one day he has miraculous reunion. “What? Is that Igni there?” “Gr-grandpa!?” It was a reunion with his grandfather, the man who was once called the strongest [Kyokuten] but was banished from his noble family because of his excessive womanizing…! “Grandpa! You said strong men are popular, but I can’t be strong!!” “Igni, listen carefully. Strong men are popular but, hard-working men are even more popular!!” “Grandpa! I’ll try my best!!!” Igni whose parents who banished Igni from the house, didn’t yet know of his obsession with being popular under the guidance of the strongest [Kyokuten] magician…!

“Igni that magic!” “This? It’s a fireball” “With this you can aim for [Kyokuten]! Come back here!!” “Nobility isn’t popular” “What are you saying?” This is a story where a young magician becomes the strongest by honing his skills all in order to become popular.

High-school student Koremitsu Akagi finds himself attending the funeral of Hikaru Mikado, who had died in an accident during Golden Week. He’s not sure why he’s there, as he only exchanged a few words with Hikaru at school. However, Hikaru doesn’t seem to be completely gone from the world, as he comes back as a ghost in order to fulfill a promise to Aoi Saotome, his fiancée. Since Koremitsu is the only one who can see him, he asks him to carry out his promise in his place.

Complying with his request, Koremitsu tries to fulfill Hikaru’s promises to the rest of his “girlfriends”, helping them overcome past misunderstandings and repair broken relationships.

Chu Mu Yun relied on his story of 《Demon Realm》 to become a one-hit wonder in JJWXC, but the him who had written seven mental cases to abuse seven mental cases to death would never have expected that he himself would transmigrate into this shitty novel!
What the hell is this system on the bracelet?
And what the hell is this either propose to seven men, or suffer the taste of a tragic death experience under the hands of these seven people?
I just wanted to write a novel to satisfy my bad interests, who would actually want to get tangled up with a bunch of mad dog sad*st crazies?

- Description from Novelupdates