MMORPG: Rise of The Dungeon Master. - Chapter 91 Library..

Violet skies, a world undergoing massive changes, a deficient moon, interlinking voids…
When the world experienced a cataclysmic event,the majority of living things ceased to exist. Although humanity survived by hiding in the last safe zones, humans had to face mutated dire beasts and colossal source beasts that could break through the space barrier and enter the earth at any second.
Luo Yunyang, a young man who grew up in those calamitous times, obtained an attribute regulator and set out to walk the path of supremacy!

- Description from novelupdates

Nagi who was summoned to another world acquired the「Skill Structure」skill.

Nagi felt the hints of black job from the king’s request 「To defeat the devil king」. He leaves the castle and starts his journey with a slave girl.

The small demon girl Cecyl, the melee-fighter beast girl Rita , Aine the onee-chan maid, Regii the cursed sword.

Rafiria the warm and fluffy elf and Iris the sea dragon shrine maiden.

Nagi rewrites the girls’ skills and made them into 「cheat characters」one after another.

Kuramoto Daisuke, a freshman in High School was suddenly exposed to someone vanishing in front of him. Turns out he was admitted to a Special Class full of Isekai Heroes that were regularly summoned to Otherworlds since the start of their Middle School. He was told that he was to become their Support to prevent each of the Heroes' fate of dying in the world they were summoned into. Though mediocre, he realized that his ability has a great potential but it needs a lot of hard work on his part.

Unconvinced of being just the Support Character, he vowed to excavate his mediocre ability, all the while supporting the Heroes using it.

And maybe more.

Young Master Lu says, “My wife knows nothing at all and has a bad temper. You’d better not bully her.” Gu Mang watches silently as this man warns everyone who comes his way.