First off, Efflite has a few attacks, which consist of him mostly bouncing around as a fireball. While it is not that dangerous, if you are not careful, it can do some decent damage to you, depending on if you are weak or not. You can hurt him when he is like this, though. He has another attack where he throws fireballs at you, plus he can make his head float around the room.
Due to having a resistance to every Weapon, you may want to focus on Magic for this Battle, it all depends, really, mainly on if your Weapons are strong enough at this point. For Magic, stick with using Jinn and the Knucks, so you can hit him from afar, but it is your call. Either way, just be sure to assault him as best as you can with whatever works best for you and to heal up when needed and be sure to avoid the lava here and you will win this.
