Shujinkou ja Nai!

Once upon a time, there was a middle-aged Japanese salaryman, a schoolgirl, and a speed demon of a truck driver. The man tried to rescue the girl from the truck, and... Well, I bet you can guess what happened next. That man was me, by the way—"was" being the operative word, because the next thing I knew, I came to inside the world of my favorite game, Braves and Blades, as Rex Tauren. Rex is the most powerful character in the early stages of BB, a level 50 jack-of-all-trades who's got tons of class skills and one huge drawback—Rex is only a minor character, so past the tutorial stage, his growth rate tanks and he's all but useless. In other words, my quest is now to find BB's true protagonist and dump all of this saving-the-world stuff on them. I just wanna kick back and... Hold up! Why does everyone keep calling me the hero?!

(Source: J-Novel Club)