It's a fairly common question, mostly because when people see 6 and 7 next to each other, it doesn't really make sense. 6 is large, muscled, and trained in multiple martial arts, while 7 is fairly average, physically, and short. However, 6's fear of 7 has its roots in childhood. See, 6 and 7 grew up together, and for a few years, they were best friends. But then 6 kissed 3, and they became childhood sweethearts. 7 secretly had feelings for 3, so 7 decided he needed to destroy 6 to win 3's affection. He started subtly, undermining 6 whenever possible with passive aggressive comments and compli-sults. But over time, things got much more insidious. 7 started messing with 6's performance in school, bringing down his grades and turning teachers against him. Even worse, 7 became great friends with 6's parents and slowly turned them against their own offspring. At night, 7 would sneak into 6's bedroom, and whisper depressing and hopeless things into his ears. Every time 3 was around, 7 would pants 6 and make fun of his genitalia, or try to body shame him in other ways. However, 3 was both smart and compassionate, and saw through 7's schemes, sticking with 6, trying to counter 7's psychological tear-down with compliments and friendship. Finally, 7 decided that he would never be able to win 3, so he drugged both 6 and 3, taking them to an abandoned cobbler's hut on the edge of town. There, he proceeded to torture and maim 3, forcing 6 to watch in horror, unable to do anything to save his sweetheart. 7 didn't kill 3, but instead, put her in a semi-vegetative state. 7 cleaned the scene of his prescence, then called the cops, having 6 blamed for 3's condition. 6 was sent to prison, believing 6 was guilty, 6's parents fell into a deep depression, eventually committing suicide over what they believed 6 had done. After serving 17 years of a 30 year sentence, and getting out on good behaviour, 6, now muscled and skilled as a fighter, thought he might get revenge on 7. But when he finally tracked down 7, he found out that 7 had installed a micro-bomb into 3's body, and should he be killed, the bomb would automatically go off and kill 3 as well. And though she was still in a mostly fugue state, 6 couldn't bring himself to hurt her any further, and decided to try and move on with his life. However, being an ex-con, it was difficult for him to get a job. 6 finally found employment at a diner, which 7 then bought, and proceeded to again undermine and toy with 6 at every turn. 6 tried to find employment elsewhere, but 7 contacted any potential employer and soured them against 6. 6 finally realized that no matter what he did, 7 was going to try and ruin his life, and he resigned himself to living as a broken, lonely man, never able to stand up to the depraved, amoral 7.