The supporting character's harem is very normal - Chapter 75 Are you leaving me here?

After Reincarnating into Naruto World at the Warring State Era as an Uzumaki, Masahiko thought that he got a useless System. He lived for 48 years as a normal, below average Uzumaki Shinobi.

That changed when he finally knew how the system works the day of his 49th Birthday!

- Description from Novelupdates

Octavius, misled by friends, embarks on a quest to clear his father's name, ultimately facing a tragic end with his sister.Their journey results in devastating loss, leaving him powerless and yearning for revenge against those who harmed his family. Spirits offer him a chance to reincarnate, but he refuses, saying;“What’s the point of a new life if I keep running from my problems”The entities are taken aback by his unwavering decision, having never encountered a spirit who refuses to escape their troubled past. They warn him about the evil being that now resides in his old body, but that only motivates him. He believed In the saying - to defeat a monster, you have to be twice as monstrous.Embracing his fate as The Phantom's Gambit, they traverse the shadowy path of retribution, their identities blur, secrets unravel, and the line between savior and monster fades.This is a tale of darkness and redemption, where justice is a blade, and revenge is the only way forward.

“Can a person suffering from amnesia have a total change in personality?”

The question lingers in Feng Ning’s mind.

Other people treat her coldly, claiming she is insidious, cunning and selfish. There were even rumors of her not being a virtuous wife and having illicit affairs with other men. However, she had no such memories.

After waking up from a heavy fall and knocked her head, she is now polite, treats people in good faith, and tries her best to get on her husband’s good side. No matter what she did, the past could not be undone and despite having no memories of it, Feng Ning calmly accepts her fate and slowly tries to mend things back. But why must fate be cruel to her? What did she do in the past to deserve this? In the first place, how did she end up in this sorry state?”

- Description from Novelupdates

Adventures of a reincarnated Old Man who died saving a kid who was about to get hit by a Truck. Reborn as the son of Duke DragonHeart, AshBorn being a unique individual with Dragonblood and elf blood in his veins he spends his childhood training with dragons and spirits of the world tree goes out into the world to adventure and climb the tower, traveling to different planets,learning the secrets of the universe as he fights an evil unknown enemy, in a perfect way of course