Quote Originally Posted by kuma_aus View Post
You have a chance of getting the upgrade items after the second boss if you save enough prisoners. The high medal cost is so that the items are rare if you're not putting in effort to do good Castrum runs and aren't just flooded on the market board.
If it has the droprate of the AV minion then I will never get one.
But good to know, so it is just for some sort of unlucky player like me.
That makes it a bit better.