you can reforge using other tools, not just essence. its a little wasteful, but you can do it. Thus for most of his 10 tools, he reforged other tools into them (not essences) until they looked like this:

2% fire resist

2% water resist

2% earth resist

2% lightning resist

2% wind resist

(whatever he wants to slot into last slot)

This is all completely aboveboard. Not the most efficient use of resources in this particular version, but its a valid strategy. And as other people have pointed, with such expensive ninjas at 4 and 5 stars, he's clearly spent a lot, which explains his stats. First thing most people put many into is initiative by refining and purifying all equipment up as high as is reasonable for their spending level.