So the AI for dragon quest/warrior 4 doesn’t know which spells don’t work against a specific enemy unless that character has fought that enemy before.

Which isn’t much of a problem until you get to the final boss. You slog through the final dungeon, heal up your party, then head in to fight the boss. And watch as your magic users waste all their mp trying to banish the final boas (which surprise, he is immune to). So in order to win you have to fight him and lose once.

My first time playing the game (as a kid) I ragequit the game because I didn’t have the patience to try the boas twice the right way. Every time I’d lose, I’d just load the game so my characters would never learn what would not work.

I wasn’t the brightest kid.