We do know that maozku are affected by sorcery (sorcery) -- Lina has destroyed several via Dragon Slave. However, sorcery derives its powers from the maozku, so it does not work like Spirit Shamanism or Holy Magic in hurting mazoku. So, I present this way of working out how a blakc magic spell will effect maozku:

Remember there are three types of mazoku. Consider also a fourth type, the Dark Lord. For review:

• Lesser Maozku, like Tiiba or Evia are threatening to mortals, but aren't as subtle as their more powerful counterparts -- they cannot interact with humans beyond the frighten and hurt because they do not have a human form.
• Master Maozku, like Kanzel, Mazenda, and Saygram are their masters' more subtle instruments -- not only can they directly terrify, but they can perform subterfuge and make deals with humans without frightening the pants off of them, because of the ability to take on a human form. On the upper side of the Master Mazoku are the Priests and Generals of Shabranigdo's lieutenants, such as Xellos and Sherra.
• Noble Moazku are Shabranigdo's lieutenants. They number exactly five: Dynast Grausherra, Hellmaster Phibrizzo, Beastmaster Zellas Metallium, Deep Sea Dolphin, and Chaos Dragon Lord Gaav. They are well-known to most spellcasters -- at least the names are -- and are very powerful and dangerous.
• The Dark Lord is a set of one -- Shabranigdo, or in this case his 4-6 remaining pieces, depending on if you count the novels, and if you count the piece frozen in the north.

Let us group sorcery spells into three (or four) groups:

• Regular sorcery spells, like Blast Ash or Disfang draw on the power of Lesser and Master Maozku. They make up the majority of the spells known.
• Noble sorcery spells, like Gaav Flare or Dyanst Brass, draw on the power of Shabranigdo's five lieutenants. They tend to be powerful spells.
• Dark Lord sorcery spells draw on the power of Shabranigdo directly. The Dragon Slave is the most famous example.
• Chaos Magic draws on the power of the Lord of Nightmares, and might not even be considered sorcery at all. There are only two know spells of this type, the Giga Slave and the Ragna Blade, and only one known caster of these spells.

Now, we look at the basic rules of the mazoku. They tend to be very hierarchal, so their reaction to sorcery should be the same way. I propose this:

• Lesser mazoku are affected by sorcery normally.
• Master mazoku are afftected by sorcery, but any Regular sorcery spell must make it past their spell resistance. Anything higher will bypass spell resistance automatically.
• Noble mazoku are unaffected by Regular sorcery. Noble sorcery will work -- with one exception -- if it bypasses their spell resistance. The exception is that spells based on their own power will automatically fail if they wish. Higher level magic will bypass spell resistance, but their damage reduction still applies.
• Shabranigdo is unaffected by any form of sorcery, save Chaos Magic (if you consider that sorcery). Were a spell to exist that drew on another Dark Lord, it would have to get by his spell resistance.