I am the - A phrase that ends fights. Once you say it, there's no comin

A phrase that ends fights. Once you say it, there's no coming back. It's like a final boss in a video game.

I am the reason you lost the fight. You're just a weakling.

I am the reason you're defeated. You're just a loser.

I am the reason you're getting the loss. You're just a nobody.