There are 8 enemy categories that weapons can be especially effective against:
Demon: Evil beings, weak to the Rune Sword.
Dragon: Reptiles, weak to the Dragon Sword.
Giant: Giants and such, weak to the Giant Sword.
Undead: Undead, weak to Fire and the Sun Sword & Light Axe, vulnerable to Harm spells, strong to Ice, Status, Stone/Poison, and Death.
Were: Lycanthropy, weak to the Were Sword.
Water: Water dwellers, weak to Lightning and the Coral Sword, strong to Earth and Fire.
Magic: Magic-users, weak to the Rune Sword.
Regenerative: Creatures that regenerate HP, weak to the Flame Sword.
There are 8 elements that weapons can be associated with and armor can protect you from:|
Status: Status changing spells, like SLEP or MUTE.
Poison: Spells that cause poison or stone, like BRAK.
Time: STOP, ZAP!, and GLARE.
Death: Spells that kill, like RUB and XXXX.
Fire: Fire spells, they hurt ice and regenerative creatures.
Ice: Ice spells, they hurt fire creatures.
Lightning: Lightning spells, they hurt water creatures.
Earth: QAKE and CRACK, they don't hurt floating or flying creatures.