Demon Slayer aka Kimetsu no Yaiba proves to be a highly-unique shonen anime involving a protagonist named Tanjirou Kamado that aims to cure his sister's, Nezuko, demonic self.
After returning from a nearby village to make money for his family, he sees them all lying on the ground in blood. However, Nezuko was the only one left alive out of all of them. As time passes while carrying her to look for help, she awakens as a demon and assaults him... but wasn't able to kill him as the real Nezuko was still within herself.
Later on a demon slayer named Giyuu Tomioka joins the scene and tries to take out Nezuko. But Tanjirou was able to get through his head to not kill her while proving his worth by almost killing him to defend her. So he let's Nezuko go and tells him to look for his master to be trained as a demon hunter like he is so as to find answers on how to cure his sister.
Demons in this anime are deadly ex humans that feast on people in order to fulfill their hunger and become stronger. And if their blood enters a human's blood system, then they too become demons and develop intense cravings for human flesh. It's like a disease that can spread to others if any are left alive.
All of this entails to representing crime that occurs day to day in this world that we live in. Rural areas are especially non-friendly areas to be in if one isn't too careful; especially during the nighttime.
Demons are shown to harm everyone around them; whether they commit murder or infect others with the demonic virus. They are just like crime that exists today where it too causes harm to communities by getting people killed out on the streets and creating victims.
The spread of the demonic virus especially correlates to how some would turn to crime in order to survive instead of living off of honest pay that may not provide enough.
Demon Slayer Opening
Demon Slayer Closing
Not all demons are the same as there are those that snatch young women, establish "turfs," and more. All of this entails to just like how there are various kinds of crime that exist today. We have sex traffickers that steal women as well as thugs that establish their own territories.
All demons could be labeled as "murderers" due to killing people, but with the different types that exist (especially those capable of using magic), they each have their own unique symbolism to represent themselves.
There are some demons that are led by a higher up to be part of "organized crime." And their leader is the original demon to ever arise named Muzan Kibutsuji.
He has been alive for a very long period of time and symbolizes as the head of a mafia that spreads crime throughout various areas. He holds the highest amount of authority as any head of a mafia would have; making other demons fear before him as they are to recognize themselves as being below him and to never back stab him.