Ghouls are undead enemies in the original Final Fantasy. They appear as palette swaps of the Zombie enemy found early on and have purple cloaks, yellow hair and decaying green skin. They later appear in the area around Melmond with similar types of enemies, in much larger packs.
Ghouls are infamous for being the first enemy players encounter capable of inflicting Paralysis with their standard attack, and have a tendency to paralyze the party's frontliners (who, at that stage, are likely also the party's main damage-dealers). It is a good idea to save casts of Fire on the party's Black Mage and to not be afraid to bust out Dia on the White Mage.
ghoul is a folkloric monster associated with graveyards and consuming human flesh, often classified as undead.A