Trema didn't seem hard to me at all. I beat him the first time.

Now I've been through the game several times, and have 3 iron dukes. He isn't even a challenge anymore except for this HP. Taking 1000000 HP off him takes quite a while even when hitting for 9999 every time. I usually just cat nip him even at this point. I hit him up without cat nip for about 15 minutes, and didn't even have him a quarter of the way there (when I fought him that last time, I only had 2 dukes and I had to keep revivng paine).