Magic in Brigandine is basically elementally (color)-coded.  I include this basic primer on magic mainly because people tend to read FAQs and web pages, but don't once crack open the booklet that comes with the game.  This isn't meant to be just a reprint of the info in the manual, but a re-examination of it, with suggestions and advice included as seen fit.

OPPOSITION Certain elemental colors are  in opposition of each other BLACK "Evil" Power <-opposites-> WHITE "Sacred" Power RED Power of "Flame and Destruction" <-opposites-> BLUE Power of "Cold and Air" GREEN Green, the color of Land and Nature, has no opposing element. NO COLOR Some Character classes and monsters have no elemental color. They have no opposing element.

COMBAT EFFECTIVENESS Opposing elements come into play during combat. Differing Character classes have  differing levels of elemental color. For instance, A Bishop is , while an Enchantress is . vs  vs  Opposing Elements Damage +20% vs  vs  vs  vs  Opposing Elements Damage +30% vs  vs  vs  vs  Supporting Elements Damage -20% vs  vs  vs  vs  Supporting Elements Damage -20%

*1 Very useful in situations such as  vs .
*2 Immediate death to enemy raised with Necro Rebirth.

*1  Beware!  This is a nondiscriminatory spell.  Allies and Foes alike will be damaged.
*2  Useful for getting a powerful monster out of the battle for a few turns.  Also good to teleport Knight; thus his monsters will be fighting out of Rune Area and will be weaker.  but caster must almost always be more powerful than target or spell rarely works.
*3  Keep in mind this is random teleportation.  You won't always like where the enemy is teleported to, let me tell you.

*1  Radiates from caster.
*2  Radiates from a targeted point.

*1  Radiates from caster.
*2  I love this spell.  It is one of those powerful ones, like curse, that will seriously mess with an enemy, especially when the caster is double magic opposing the target.
*3  A relatively useless spell.  Despite the claims in the effectiveness column, it does very little to the enemy.
*4  Since part of the purpose of battles is to level up monsters, this spell can be a double-edged sword.  Use only if you are in a serious jam and don't want to retreat.  Otherwise, the enemy monster, although fighting its allies, accrues experience!  If you ultimately have to retreat and it survives the battle, then you've just aided your enemy.
*5  Monster fights randomly.  You do not have control over it.

*1  Called "Protec" in the manual
*2  Seems to have more effectiveness when your enemies cast it upon themselves than when you cast it on your allies.  Nevertheless, can be a useful spell, especially when target is subsequently attacked by lower-level enemies.
*3  Another very useful spell.  If you have a high-level caster, use this against an enemy with high physical power and attack power.
*4  All jokes aside, this is another situation like Charm.  Though enemy is completely immobile, its status of being turned to stone weakens physical attacks made against it.
*5  I love this spell.  This is just about the only think fairies have going for them in the English edition (in the Grand Edition, they can cast Thunder!)  Useful when you want to the target to cast a powerful spell twice (target's available MP withstanding), or when you want the caster to be able to move and cast a spell or vice versa.
*6  Success rate of this spell is especially dependent on ratio of caster versus target.