Chaos Legion/Monsters

Monsters are classified as either Organic, Non-organic, or Metallic. Organic enemies are composed of flesh, blood, and bone. Metallic enemies are made of gleaming matter. Non-organic enemies are somewhat made in the middle of the two types. Blasphemy Legion's Crimson Carnage works wonders against all monsters and bosses, especially for the "revisited" stages. This is highly recommended for most stages. Even if not listed, Thanatos is considered effective against all enemy types.

Organic
This type of enemies include Balors, Ogmas, Badbhs, Zeodagdas (Ninjas, and Gunners), undead Zombies (Soldiers, Commander, Gunners, and Cannons), Jenons, Seedlings, Galarges, and the body of Rudo Garias. The main feature of organic enemies is the color, which is related to nature: white, gray, brown, green, red, etc. Organic creatures are usually animal-shaped, and have visible veins or bloodstains.
 * GUILT, HATRED, and BLASPHEMY will make short work of them.
 * Note: do not confuse a bloody gray Zombie Soldier (organ) with a shiny gray Zombie Soldier (metal). Such mistake will be real trouble.

Non-Organic
This type of enemies include all forms of Danus, Golems, the shields of Rudo Garias, and all floating mines. The anatomical composition of these monsters remain unknown. Flawed and Blasphemy are the only Legions that can destroy floating mines without suffering too much damage. Blasphemy can also destroy RG's shield in one blow, as well as heavily damage a rock-hard Golem.
 * FLAWED, BLASPHEMY, and ARROGANCE will obliterate them.

Metallic
This type of enemies include Gunners, Archanus, Cannons, and silver Zombies. Metallic enemies have a shiny look when first seen, so deploy your anti-metal Legions. Several metallic enemies have ranged weaponry, where Malice and Arrogance both excel. Silver Zombies are the hardest to kill other than Golems. But with Perfect Thanatos, Sieg's life is a pure party... anything else is doomed.
 * MALICE, FLAWED, BLASPHEMY, and ARROGANCE will decimate them.