I am not sure if this is spoiler or not as this is an enemy in later episodes and not a boss.

For anyone who hasn't seen him yet and wants to know what I am talking about, he starts with 0 dice, gains an extra dice each turn, only has one attack (nightmare) on which he has to accumulate 99 points over the turns, and this attack deals 999 damage. He has over 100 health points.

I only fought him twice so far. Encountered him on 2 runs so far. Once as the thief, once as the robot. With the thief, I had to flee on the first attempt, and was lucky enough to be able to buy the equipment that allows you to survive a fatal blow for the next 3 turns. Then I started the fight again, and on the turn right before I suspected he be able to use his attack, I used my new equipment to get 3 extra turns. The additional turns allowed me to finish him in time.

On my second encounter, as the robot, he crushed me :D

I really like this enemy. Even though he is tough and you need specific builds to be able to beat him, I think it is a nice, original fight.

Edit: Fixed my Spoiler tags.