There. I won. After almost 8 or more hours for the first form of the boss, I fought the last one. Win or lose, I was done. Stick with vanilla FFT or turn the game off after Velius. Chapter 4 is not worth it.
This guy was tough! After trying various things, I decided I was going to try to just whittle the guy down with Mind Charged Last Word blasts, and keeping the side demons busy with buffs and debuffs.
I wanted to get to Pixie and Parvati since they have the lowest MP and could maybe run out, or since they have the lowest HP, I could kill them fast to avoid the whole Recarmdra thing.
The last battle with Lucifer, using only the Demi Fiend. My abilities at this fight were: War Cry / Endure / Diarahan / Rakukaja / Life Surge / Avenge / Freikugel / Pierce. I dropped Focus so I wouldn't bother with using it/risk an Avenge counter used it up. I used Diarahan to avoid farming Beads.
Ailments are bad in this fight, since if I am poisoned, Pale Rider can do an insta-kill with Pestilence, and if I am put to sleep by the Dormina spell, Pale Rider can also instantly end the fight with Eternal Rest.
The main decider in the victory was hoping that the Loas held off on using Debilitate for a long time, so I could get rid of Pale Rider's MP.
After about 4 hours of trying to beat this guy, I got the win.
The toughest fight so far, Pale Rider is a super jerk.
My abilities in the fight are: Rakunda / Tornado / Fog Breath / War Cry / Focus / Mana Drain / Diarama / Tarukaja. My magatama was Anathema (Null Death, Weak to Expel) so the enemies could lose 2 turns if the Loas tried to use Stone Gaze.