In Max's narration, he refers to many nicknames given him by the people in his life.

From the text:

Called me Kicker for a time – this was day care, the year Gram and Grim took me over – and I had a thing about booting anyone who dared to touch me. Because they were always trying to throw a hug on me, like it was a medicine I needed.

Mad Max they were calling me, or Max Factor, or this one butthead in L.D. class called me Maxi Pad, until I persuaded him otherwise.