The Sea Cruiser and Underwater Temple sequence is… punishing. I’m glad Innocent Sin taught me to always stock on HP and MP items to the max. Still, the Underwater Temple is full of trapped floors that make you repeat the same sequence over and over again. And unlike trapped floors in Innocent Sin, those are only visible on the minimap.
During fight with Chizuru in the temple, I simply got lucky. Persona 2 loves the “shell game” mechanic. Boss summons 4 clones, then swaps places with one. Clones have some reflective properties, either a particular element or like in this case all of them. You need to guess which is the real one, and once you do, clones disappear, then the process repeats itself. Chizuru also casts Rage, which doubles the physical damage, but makes character attack at random. Which is usually deadly, as 4 out of 5 enemies would reflect the double damage right back. But this time, it simply worked in my favour, finishing the boss off.