I Become A Mob Character In A Novel

I...AM...MOB!!! Sigh~ My name is Samael, I was an office sla- I mean a worker who worked 9 to 5. It was a daily routine of monotony until one fateful day when I went home only to find my best friend with my girlfriend. Betrayal was the first thing I felt, followed by rage. I turned around and left while the mocking laughter of the two echoed in my ears. They thought I was a loser who couldn't catch a break, but little did they know, I swiftly entered the kitchen of my small apartment and grabbed the knife I used to cut vegetables. It was time for revenge, a drastic one. I again turned around and marched into the living room, the glint of the blade catching the dim light as I approached them. Directly plugging the knife inside my girlfriend's neck, As the blade pierced her flesh, Blood sprayed on the face of both my best friend and me. Shock registered on their faces as they realized the gravity of the situation. But it wasn't enough. I wanted them to suffer, just like they made me suffer. In a fit of rage, I lunged at my best friend, the knife still in hand, and with each stab, I felt a rush of exhilaration. It was as if a primal instinct took over, driving me to seek vengeance at any cost. Blood pooled around us, mixing with the tears of betrayal. But as I stood there, surrounded by the aftermath of my actions, something strange happened. A blinding light enveloped me, and when it faded, I found myself in a world completely unfamiliar to me. Gone were the familiar sights of my apartment, replaced by a luxurious bedroom in a grand manor. Confusion gripped me as I tried to make sense of my surroundings. It didn't take long for me to realize that I had been transported to another world—an isekai, as they called it. Looking at my reflection in a mirror, I noticed my appearance had changed. Gone was the face of the disgruntled office worker; instead, "SAMAEL ASHWOOD!!!" a character from a novel I used to read. But this wasn't just any character; I had become him—the sacrificial best friend of the protagonist who was betrayed and died in just the first two chapters. PROTAGONIST DIED!? [Heavenly Destiny System Initializing...] [...] --------- A/N A vast world where power is law! There are many protagonists to plunder from! Tags: #Yandere Heroines, #Teacher-Student Relationship, #Elves, #Demons, #Beastmen #Maid, #Vampire, #Angel, #Incest...Etc