Reincarnated as a demon lord with a system

The name of the protagonist is Caam. He is originally from Earth, but after death, he was reincarnated as a demon in a fantasy world. In a world where only the strong survive, he was left with no other option but to fight to save his neck. This led him to become a mighty warrior, even if he didn't notice it. By the time he notices how powerful he is, something strange happens. The story begins when a more powerful demon appears before him. Instead of fighting with him, the demon acknowledged Caam's strength and asked him if he wanted to become a Demon Lord. He couldn't refuse the offer, and that's where the main plotline explodes