The Days of Being the Richest Man in the Ninja World - Chapter 342. Too Evil! Too Black!

Scheming female assassin transmigrated to become the weak Eldest Miss, her story is wonderful and stunning, attracting peach flowers to blossom open. Cold calculating emperor? Genius bad crown prince? Insidious happy-go-lucky prince? Gentle physician? Ice-cold mystery male? Who is her true love? Haha, but she only eats, definitely will not take responsibility! Beautiful men be careful!

- Description from Novelupdates

I became the childhood friend of the protagonist in a novel. The childhood friend who died from taking drugs.

The world had changed when the System arrived, alongside the Cataclysm that filled the world with monsters. The technology was gone, replaced by classes and skills that allowed the people to fight back. When Devon ended up as a Blacksmith, a class that didn’t grant Intelligence, he had to face the reality, that his old career that he loved - mathematical sociologist - was over. Instead, he had ended up as yet another discarded member of the production class, overshadowed by the existence of the System Shops to the point of total marginalization. But, what if all he needed was to reapply his scientific thinking to the System...

Although born in a wealthy, powerful family, Shangguan Ning is motherless and loveless. Throughout her growing years, people use her for their own interests.