Baka to Test to Shoukanjuu‎ - Volume 7, The Eighth Question

A serious accident caused the protagonist’s brain to have an unusual mutation. This changed the brain development that it opened the door to a mysterious universe. Not only he obtained a ‘god-like’ powerful telekinetic control and mental perception, he also had an abnormal analysis and memory capability comparable to super computer. Having such super brain, his rough life began.

Brain development progress 10%…….20%……50%….80%…. …100%

- Description from Novelupdates

On a certain day, Xu Xing suddenly received yin-yuan eyes; he could see a red string between lovers. Then he discovered that he had a tight connection to his own left hand.

Xu Xing: I TM …… will I be ‘solo’ for life? : )

The second day.

Xu Xing suspected that he had seen a pair of ‘gay’s. The left side of the boy’s body had two red strings. The one in front was tied to his hand, the one in the back was tied to the boy’s right side.

The bottom of Xu Xing’s body suddenly tightened. Trembling in fear, he turned his head — only to see his ‘local area’ connected to a red string tied into a beautiful, intimate bow that was attached to the school grass sitting behind him ~

Xu Xing: Excuse me???

- Description from Novelupdates

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.