ABO verse with a twist.
In a world where the Alpha serves as the lowest caste in the society, Eren Jaeger, a born alpha and a renown doctor's precious son, has to find an Omega to take him in before he reaches his adulthood, otherwise he would automatically turn slave and be expelled from the capitol city. Trying to save his only son from the terrible fate, Dr. Jaeger pleads the King to set up a meeting with an unmated Omega suitable to his son. However, when the scheduled time comes, it is the notorious Alpha killer, General Levi Ackerman, showing up at Jaegers' door...
The story is written in Mandarin. (sorry!)