The Vocation is a role that describes the attributes and characteristics of a character throughout the game. The System is the set of rules and requirements for changing a given character's vocation in Dragon Quest games. Only certain games within the series use a vocation system, with others having traits permanently fixed to characters. The system is always tied to the Alltrades Abbey present in the respective games, wherein characters can switch professions or combine past experiences to unlock advanced positions.
In III, the player begins with only the Hero and can enlist up to three additional party members from Patty's Party Planning Place. These characters represent different vocations and it is up to the player to decide what party members they want for their team. Each of the jobs had its own strengths and weaknesses which allowed the player to build a team based on their own preferences. At any time, the player can leave and replace party members here. The party members who are kept in the tavern with whatever stats and equipment that they gained during their travels.
About halfway through the game, the player will reach Alltrades Abbey, which will allow the player to change a character. Changing vocations drops a character to level 1 with half of their previous stats (and all learned spells if any), allowing particularly patient players potential to develop a perfect character without resorting to seed searching. The Sage is a hidden vocation unlocked by bringing the Words of Wisdom to the abbot or through getting a Gadabout to level 20. The Hero cannot change class at any time.
Unlike in III, this game starts with nine available classes. Each of the classes has eight ranks that can be reached by battling the required number of monsters, unlocking new abilities at each interval. Through mastering the initial jobs, advanced classes can be unlocked for the character. For example, by mastering the Warrior and the Martial Artist classes will allow the character to become a Gladiator. Skills and spells mastered in one profession are permanently learned by a character.
The vocation implementation remains mostly unchanged from the previous game, though in the original PSX version there existed hybrid abilities that were unlocked through mastering certain positions sequentially. For example, a character could master Sword Dance by mastering the Warrior vocation right after the Dancer. This aspect was removed in the 3DS remake, with the hidden abilities being incorporated into the normal repertoire.
Finally, party members can also become monsters by using Monster Hearts. By putting a monster heart in their inventory and speaking to the abbot or High Priestess Jacqueline, they can become that monster. In the PSX version the character would not take on the appearance of the monster until mastering the vocation, where as they immediately become beastly in the remake. Furthermore, monster classes are the only way to permanently learn advanced skills and spells in the remake.
In all, there are over fifty classes that a single character can become in this game.
IX has a system which is similar to the one in III, in which a vocation defines a character and where the player may create party members and add them to the party. This can be done at the Quester's Rest located in Stornway, by speaking to Patty. Party members created do not play any significant part in the plot.
Vocations can be changed at the Alltrades Abbey, after the player has rescued Abbot Jack. There is no minimum level limit for changing classes, dubbed Re-vocating. One notable difference from past games is that spells are no longer carried over between class changes. A character must be a specific class to use that classes spells. Skills do carry over, and there are also methods for utilizing each weapon type with all classes.
Additional vocations must be unlocked by doing quests before the player can switch to them. Notably, the Sage class is accessible only later in the game, but includes a specific ability, Jack's Knack, which allows the party members to change class at any time and place.
There are a total of 12 classes available in IX.
Maribel presenting all human vocations available in VII