At the start of the game, you must choose one of four classes. This decision will impact how difficult the beginning and ending of the game will be.
Fighters are the most balanced of the four classes. They are only capable of learning the first six spells, but they excel in combat. They don't excel in any one area, but they can increase their attack and defense levels to the highest among all classes. This is generally the easiest class for beginners to try.
Thieves, unlike Fighters, excel in physical power. They can equip themselves with the most powerful weapons, and can carry much heavier loads at lower levels than other classes, which is good because this class needs to carry around more supplies. They are also quite adept in disarming traps in treasure chests. In exchange for these abilities, they have considerably lower intelligence, and the six spells they can cast aren't very effective. They also don't possess a ton of charm, so expect to pay a little more at shops. This is an easy class to start with, but a hard class to finish with.
Clerics are the masters of magic. They gain the most magic points, they can learn all twelve spells, and they are quite effective. In exchange for this, clerics have lower attack and defense strengths, making them a bit more vulnerable in battle. It is recommended that clerics fight with ranged weapons to be safe. This can be a hard class to start with, but it gets easier to finish with. To compensate for this difficulty, they earn experience at a faster rate during the first five levels.
Monk is an extraordinary class; they are strong, can fight well, can learn all 12 magic spells, and their stats grow to very high levels throughout the game. They only have one specific weakness: their physical health. Monks tend to have the lowest amount of HP of all the classes, making them susceptible to damaging attacks. While monks generally have an easy time getting through the game, you will constantly have to monitor their health and keep them safe when they get attacked. For this reason, they are considered a class for expert players.