I'll Teach You, Marianne. - Chapter 616 - Rothschild Dynasty?

A man was transported to Ancient China and eventually became a servant of a declining household without a male heir. He utilized his wits and modern knowledge to help the household and eventually become trapped in the sea of political turmoils of the period.

- Description from Novelupdates

After the nuclear warfare, massacres started to spread throughout the entire world. The order between humans completely collapses, and the strong eats while the weak gets eaten becomes the #1 rule.

In a world where everyone is undergoing their profession's transition, I've surprisingly awakened to two professions.Moreover, I've also awakened a defiance lifestyle profession.Preserve high-quality items? I'll just synthesize them.Preserve high-quality skills? I'll synthesize those as well.Preserve high-level pets? I'll keep synthesizing. Wait, why is this beast-girl so large after the synthesis?Let's start by synthesizing three “Skeleton Summonings.”Synthesize into—The “Undead Army.”Now, let's synthesize three Dark Wands.Synthesize into—The “Death's Scepter.”In the grand interspecies gaming contest of the universe, can we, humans of the Solar System and Earth, ascend to an even broader stage?......

When she woke up, Lake returned to the classroom of the third year. The classmates were in class with swords and sticks, and the teacher became a female Taoist.
The little fat man in the back seat, how to put two big hammers under his chair.
Rick found this to be a global era!

- Description from Uukanshu (translated)