Red Rider's worse. Much, much worse. Have fun! :D
No. He does spam Sukukaja though.
Really, they're throwing back to SMT I and II more than III in this case.
Anyway, there are a few rules of thumbs when it comes to fighting fiends.
1. Do NOT have everyone null/drain/repel whatever they use, lest you suffer almighty spam that they wouldn't do otherwise (Except Red Rider. He'll do it anyway, just less often.)
2. Don't uses buffs or debuffs three times. They'll just Dekaja/Dekunda it. 2 times works though.
3. If you die to them and pay Charon to revive you, they'll still be there. You can even save and quit and then reload and they'll still be there. Just don't say no when you're prompted by the messages.