Olax, like any experienced fighter, had his tactics for fighting against both monsters and Phantoms. Many people didn't realize it, but unlike Upper Ring Phantoms, Lower Ring Phantoms usually had quite a bit of experience fighting against other Phantoms.
This was logical, it was quite rare for truly bloody and deadly battles between Phantoms to occur in the Upper Ring.
The Big Three, the military, and the government did their best to make it happen as rarely as possible because the main enemies of the Phantoms were monsters, not humans.
However, this had its negative effects, there were fewer Phantoms in the Lower Ring, but on average, each of them was much stronger, especially in a battle against humans.
Thus, Olax's confidence in victory was more than reasonable, especially against an archer, but... Upper Ring was not a paradise. Many Phantoms in the Upper Ring had to go through just as hard a life as the dark Phantoms, and it seemed Fred was one of them.