I got this game recently, and consider myself incredibly fortunate to have been able to do so. However, I’m a bit stuck.
I’m at the part where you have to fight Matador, and he kicks my ass every time. I realize that this game has a lot of variables in regards to ways you can build up your party, but all the same, some tips would be appreciated. My protogonist is at level 17.
Just saying what level your protagonist is tells us pretty much nothing. We need to at least know what skills you know and some idea of what your party members are. I would also consider leveling up some, as right past Matador (If I’m thinking of the right place) is a longish area filled with enemies around level 25 which may prove fairly tough. Matador is a bit of a pain to fight, since he’s so damned strong compared to anything else by that point. Try bringing in lots of force immune allies and users of sukunda, fog breath, tarunda, war cry, tarukaja, rakukaja or sukukaja, as those spells are all broken as hell.
My protogonist knows, at the moment, Lunge, Analyze, Life Bonus, Tarunda, Fire Breath, Berserk and Dia. My main party consists of an Angel, an Erthys and a High Pixie, although I’ve been training anf fusing some new demons for this fight. I’ve managed to get a decent Shiissaa and a so-so Chrononzon, and I just got a Nozuchi, which is immune to Matador’s Mazan spell. Unfortunately, only my Angel knows Dia at the moment.
Fuse the angel and the high pixie, which should net you Megami Uzume, a decent healer that is immune to force and learns media. There is a force immune magatama available somewhere near where you are at (in a shop, maybe), which will help you a lot. Try and find replacements for lunge (not worth the hp cost), analyze (you get an item that does this later, and there’s always gamefaqs) and life bonus (not worth the slot, you would be better off with an elemental resist).
Some skills to look out for: Mana Drain (lets you rob an enemy of 20ish mana and give it to you), Focus (triples next physical attack, absolutely vital for some bosses), Tornado (massive wind damage to random enemies), Magma Axis (this won’t show up till much later, but does absolutely monstrous fire damage to one target and might work with focus), Divine Shot (one of the 3 best single target physical attacks, won’t be showing up for a while), Endure (survive any 1 attack with 1 hp, absolutely vital).
I was told that I needed to keep my High Pixie unfused to unlock something later.
In any case, I leveled a bit and did some new fusions, and I think I have a shot now. Thank you muchly for the advice. 
No, you can fuse the high-pixie as long as you never get rid of the fused monster, and STILL get the awesome unlock.
I’m going to take your word on that. If I don’t get whatever it is, I shall be most cross with you. :ah-ha!:
Christ, I need to finish this one of these days. I think my save is somewhere 3 levels down into the deep labyrinth and after that jail/school/ice snake thingy. Elementalists represent.
You don’t need to ‘keep’ any monster so long as you have registered them in the Demonic Compendium. That way any monster you have dismissed or fused can come back at that level. For a fee, of course.
Yes, AGI dropping abilities are the jam right here. Fog Breath is what you want, though, as using anything else will waste attacking time. Two is all you need until (if) he boosts it again. An AGI Boost to your party just once wouldn’t hurt.
I forget if he has any weakness to an element. Find it and exploit it of course, but if he uses an elemental attack, find someone who’s against it. This goes without saying as this element makes up half the game, but just to throw it out there.
Oh, HP-using Physical attacks at this time/location = NO. They miss too often to make up for the slight additional damage a successful hit would tack on.’’
COUNT on expecting some of your party to die. Keep really good backups because shit WILL happen.
Good luck.
Yay, I beated him. 
With a bit of luck, a Media user and three-quarters of my party completely immune to one of his attacks.
Thanking people again for the advice. 
Welcome to Nocturne.
Don’t worry too much about the pixie unlock. You can only get it on one ending path (the True Demon ending) and all you get for it is a pixie with 30 on all stats and a bunch of level 3 attack all spells. Kinda handy, but the lack of resistances and support spells makes it just fusion fodder as soon as you get it. All you need to do is keep track of what demons you fuse your first pixie into and don’t tell them to fuck off.
Good luck with the Hell Biker.
Hell Biker is pretty easy, Matador just is a son of a bitch because you’ll probably end up having to grind 4-5 levels to grab a Megumi Uzume.
Most bosses after Matador are fairly easy, since you have a lot more options to play with. Matador is the only one of the fiends that you have to fight, which makes it that much worse since you can just go past most of them and come back later.