Did you know that the Captains in Phin can be beaten very easily by using the correct strategy?
You don't even need high HP, because the strategy involves frequent use of the LIFE spell anyway.
This is how you do it: level up your LIFE spell until it reaches LV3, or higher.
Then put the character using LIFE in the back row, and everyone else in the front row.
Now keep casting attack spells on the Captain (physical attacks work too, but spells are much better).
If a character dies (and this will happen), use LIFE on that character.
Now if you just know that a char will die the next turn, still give that char an order, because in this game even revived characters will execute their commands before the next turn.
Personally I use this strategy:
---FRIONIEL
MARIA
GUY
GORDON
Frioniel stands in the back row and uses LIFE 3 on anyone that dies.
Maria keeps casting FIRE 5.
Guy just swings his axes.
Gordon casts ICE 2.
Sometimes I take a good guess on who's about to die, and I usually pick Maria, since she has the absolutely lowest HP; and then the next turn she dies alright, but since I've ordered her to throw FIRE 5 she'll still do that before the next turn.
This stategy works even better in FF2 Origins, because in that version the LIFE spell *always* works, even when it's used on several characters at once.
Well, try it.