There's a kid at school everyone knows. It doesn't matter who he is - an athlete, a member of the band, or a member of the math club. Everyone knows this kid. Everyone knows him because he's a fixer.
Eric has always enjoyed fixing things. When he was a child, he liked taking things apart just to put them back together. He'd study things to see how they worked. He took apart a phone, a computer, and even helped his dad take apart a car motor.
What's fascinating to Eric is figuring out how things work. He studies things very logically and in order. What are all the things that happen when you turn the ignition on a car? Eric knows. All this knowledge is very helpful to Eric as a fixer.