>>11810264It's supposedly even more rare than the Mysterious Hat (1/256 on a single enemy), but I got it once in the NES version too (unlike the Mysterious Hat which I'd swear, like some others claim, was literally impossible to drop on NES until I checked the game code and saw nothing to prove that).
>>11809637You can use it any number of times you want. Also loading the save you back at the last priest you saw and not where you actually saved so it's not very useful.
>>11809919Well then you probably need to grind more.
There are two other possible tactics I didn't mention: use cursed items like the Sword of Destruction and the Gremlin Armor and hope you get lucky with the cursing. Some people swear it works for them but others say it's not worth it, I never tried it myself.
The second one are OHKO spells. I can't remember if the Cannock's Sacrifice works on bosses, but the Princess's Chance spell definitely does. One time I was against one of those late game bosses and only the princess was left with little hp, she was going to die on the next turn guaranteed. I had her cast Chance and she made the boss disappear, after dying to a mob and coming back to the castle I realized the boss wasn't coming back and I laughed my ass off.
However both Sacrifice and Chance are learnt at higher levels than you currently are so again you probably just need to go back to the last room of Rhone and grind a bit, it won't take that long