I found somewhere in the event description that the more you beat it, the higher the chance is for a higher lvl ccapac apu. So far the highest I've seen is lvl. 400
Well, I already defeated it 25 times and the 25th was lv 300, took me 3 duels to nock him out, regardless... If you had defeated even more than that, you should see lv 200 sometimes when it appears or rarely lv 300-400. But mostly lv 100 is still a pain in the neck