The supporting character's harem is very normal - Chapter 443 Is this your answer, Lathel?

Growing up with eccentric materialist parents who left him in the care of his grandfather for a job overseas, Zhang Heng had learned to adapt and be unfettered by the oddities and challenges in life. But he would soon learn the baffling truth about the world he thought he knew when one day at midnight time froze and he found himself in a world so quiet and still it was deafening. That night, he discovered that he had 24 hours more than everybody else and thus, marked the beginning of his adventures. The mysteries surrounding his newfound ability only deepened when a strange old man claimed to have given Zhang Heng that ‘gift of time’ and recruited the young man to participate in a cryptic ‘life-changing’ game on his behalf. Little did Zhang Heng know that accepting those terms meant embroiling himself in many versions of reality and exposing himself to the hidden secrets of the world—a decision he could never undo.

In an era where humans and demons compete in fierce battles for survival, the Hero has fallen.“…I will take your place.”Thus began the deception of the fake Hero.If exposed, it could mean the destruction of humanity.…But the imposter is just too good at it.[Academia], [Professor], [Hero]

mc gets transmigrated to Fallout New Vegas with the merchant system. let the questionable adventure begin.

When The Cute Kunoichis Spied on Their Teacher's Secret is a light novel written by Kazuma Kamachi and illustrated by Ryuushi Tajima.

The story takes place in a world where Japan never ended their isolationist phase, and agents from foreign powers are always threatening to steal the country's advanced technology. In order to combat this threat there has been a resurgence of ninjas that use Strategic Martial Arts, techniques that combine cutting-edge modern technology with a traditional foundation of martial arts and ninjutsu. The story follows Souha Sugiyado, a 17-year old ninja instructor and former ninja prodigy who was forced to retire from active duty by the wounds he suffered in his last mission. Souha's four students are all kunoichi who have all gained the rank of Elite Ninja, the highest official rank available to ninja. However, one day two Shogunate ninja approach him with the news that his four students have gone rogue and have stolen a portable modular nuclear reactor, and thus they ask for his help in bringing his students to justice.