Sure as killer-man Jarrow rises like Olympus above the Serengeti

The story:

I was singing this song over and over again, thinking about who the hell was killer-man Jarrow. I convinced myself that he must have been an ancient african hero or something like this. After a while I met a friend whose english was much better than mine (we both are Germans) and she told me the right words. I had been very proud of my "good" english until then...