The heroine = n younger brothers + the future successor of the SL gang
Male protagonist = younger brother of SL Gang + future successor of SL Gang
The male and female protagonists have been childhood sweethearts since they were young. The heroine's father is the founder of the world's largest gang and is also the boss of the gang. He is the successor of the heroine's SL gang. The male protagonist is the heroine's bodyguard, also known as childhood sweethearts. They fall in love and kill each other.
Purpose: Childhood sweethearts