The supporting character's harem is very normal - Chapter 13: This is your portion

A master of Chakra Cultivation sacrifices everything - only to be reborn with a second chance.After giving his life to save his world, Alaric awakens in the body of a child. In this new realm where power is measured in tiers, bloodlines, and the strength of one's oaths, Chakra Cultivation is an unknown path.As Alaric purifies his chakras, each one unlocking profound abilities across body, mind, and soul, he gains an edge no native warrior can match. But his true test awaits in the Tower of Trials—a rite of passage for the world's young elites, offering immense rewards to those who can climb its treacherous heights. No one has ever reached its highest levels.If mastering his reborn powers wasn't hard enough, his journey will forge a bond with an entity of unimaginable strength - and lead him to lands where no mortal has dared to tread.

Lin Wudao has traversed, and there is an invincible corpse collection system.

As long as you collect the corpses for the strong, you can get the things they owned or touched as rewards during their lifetime, and the obtained items are still strengthened.

Lowest, ten times stronger!

[You collected the corpse of the great emperor Jiang Taichu, and gained ten thousand years of cultivation! 】

[You collected the body of your fiancée Jiang Qingxue, obtained the Zichen Sword, a humane spirit weapon, and after strengthening it ten times, it was upgraded to become an extreme spirit weapon, the Xuantian Ancient Sword! 】

[You collected the bones of an immortal, obtained a ray of immortal origin, enhanced it by 100,000 times, and upgraded it to become the original origin of Hongmeng. After refining it, you can be promoted to the immortal emperor! 】

…

Since obtaining the invincible corpse collection system, Lin Wudao has embarked on an invincible road that can push through the ages and suppress the heavens.

- Description from novelbuddy

At first, when he learned that he was forced to go to many different routine worlds and be reborn into all kinds of cannon fodder, he was against it.

Ian Percus, the second son of a countryside Viscountcy.

One day, he received a love letter from the future.

‘If we don’t protect the future, the world will perish.’

With an ominous warning scribbled by someone