MTL - I Am a Summoning Master - Chapter 12 crisis

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

A young man with an extraordinary mind is off on an exciting adventure when he mysteriously wakes up in the body of a feeble slave-guy in a different, rich in quirks world.

The main character, a selfish jerk, would use extreme means to achieve his goals. However, he never allows his base instincts to overrule his sense of decency. He always pays back both good and bad deeds.

Will his (terrible/excellent) mentality help him make a fresh start? Will he get through misfortunes and hardships of the new world?

There are 5 books on the 6 sworn brothers in a serial called streamer (流光系列). ‘They are rich, handsome and powerful. These book are on various types of love as well as on the bond and mateship between the brothers. Book on youngest 6th brother.

Chen Yu Bai (3rd brother) & An Xiao Yi – Chen Yu Bai is a sharp, domineering & cool man whereas An Xiao Yi is a foolish, childish & innocent girl. He is her boss & she is his secretary. He bullies her yet at the same time will not hestitate to protect & shelter her. Thus, she can always rely on him. Their relationship is a funny one on how opposite attracts.

Li Wei Ran (5th brother) & Qin Sang – Li Wei Ran and his cousin Qin Song fell in long with Sang Sang who is An Xiao Yi’s best friend. Sang Sang sees Li Wei Ran as a good man. He is polite, patient and passionate whereas she is independent, intelligent and interesting. They are a perfect pair but she is afraid to love so he has to work hard to convince her he is worthy of her love..

Short sequel on their children.

Lucien, a guy who has nothing but the desire to save his mother. To get strong enough, he makes a contract with the demon of L.u.s.t. And now, only by making a great harem, will he gain the power to protect those dear to him.