The supporting character's harem is very normal - Chapter 479 Pathogens

After putting a suggestion to add a mercenary in a bad Murim novel he read, Leo would finish a mission with his NPCs before sleeping. Or so he planned. For some reason, he was transported into the said novel as the extra mercenary added by the author. His loyal NPCs, a yandere secretary, a happy-go-lucky assassin, a sexy puppeteer, and two weapon maniac guys start to become sentient. He lead his mercenary band ’Hallowed Insects’ toward an an unprecedented future in a Murim most turbulent era while enjoying his time. Fortunately, they still have their futuristic equipment with them. Tang Clan have a Poison Dagger, they have a Photon Sword. Shaolin Sect has a Qi Blast, they have a Railgun. And of course... “How much are you willing to pay to employ us? By the way, Demon Sect pay us 50,000 Golds to join their side in the upcoming war.” ... he always sided with the highest bidder.

Naofumi Iwatani, an uncharismatic Otaku who spends his days on games and manga, suddenly finds himself summoned to a parallel universe! He discovers he is one of four heroes equipped with legendary weapons and tasked with saving the world from its prophesied destruction.

As the Shield Hero, the weakest of the heroes, all is not as it seems. Naofumi is soon alone, penniless, and betrayed. With no one to turn to, and nowhere to run, he is left with only his shield. Now, Naofumi must rise to become the legendary Shield Hero and save the world!

[ this article is sweet and pampering, and it's all over. I recommend this new article: Cheating Daddy: Mommy, LET'S ELOPE! ]

An advertising director is reborn in 1988 Hollywood as an eighteen-year-old blond-haired westerner named Eric Williams.

From then on, he starts writing movie scripts and television songs, becomes skilled in directing every kind of film, wins over all kinds of female celebrities, and takes the road to become a Hollywood legend.

- Description from Novelupdates