Which do you gravitate towards in the classic triptych?
This is the absolute base level. This is the main fantasy. Codefied by fantasy roleplaying games such as Dungeons and Dragons, all the possible classes boil down to some offshoot and/or combination of the three main archetypes: the Fighter, the Mage, and the Thief.
(As a quick aside, some people - myself included - tend to count the Cleric as the "Fourth Archetype" when explaining games to others. In fact, the original "launch" of D&D had Cleric as the third base class option instead of Thief. However, that has more to do with its group role, which will be covered in a later chapter. Mechanically and thematically speaking, Clerics tend to be more of a Hybrid - also set to be covered in a later chapter. As such, for the purposes of this series, we're leaving the Cleric alone for now and keeping the archetype triangle as it stands).
Each archetype deals with a specific fantasy, and generally dictates the ways in which you meet various challenges throughout the game.
The Fighter (or Warrior) is often the simplest archetype and thus many people's default. The Fighter has a lot of strength, a lot of durability, and tends to solve all its problems by picking up a large weapon and pummeling the problem in the face until it goes away. While generally the least damaging of the three in terms of raw output, Fighters still hit hard when they do hit and can survive more counterattacks.
The Mage (or Wizard,) is the flashy and theatrical counterpart. Mages use powerful and visually impressive magic spells hurled at deadly accuracy to reduce enemies to ash in a matter of seconds, or otherwise alter reality to suit their needs. The trade-off for such immense potential is the fact that they are generally so frail that a stiff breeze can take them out of commission. After all, heavy armor gets in the way of ritualistic hand movements.
The Thief (or Rogue) is the balance between the two. More durable than the Mage, but still not nearly as the Fighter. More damaging than the Fighter, but not nearly as much as the Mage. The Thief is more cunning and tactically-minded than the academic Mage or the brutish Fighter, using battlefield positioning and dirty tricks to get multiple hits in and speedily getting away before the enemy realizes what hit them. Oftentimes stealth becomes a core mechanic, but not always.
These archetypes don't necessarily need to keep to fantasy. You can find modern "realistic" examples of these archetypes if you have three characters where one is more physically imposing and in-your-face, one is speedy and sneaky, and one is weak but knowledgeable and prefers to let some form of technology do the talking. And, as hinted before, a later chapter will discuss ways these archetypes can overlap and become Hybrids.
The last thing I want to touch on here is how these archetypes typically progress. While a Thief-type character is consistently only as effective as the player is at exploiting the mechanics, the Fighter and Mage tend to have an interesting dichotomy called "Linear Warriors and Quadratic Wizards."
What this means is that a Level 1 Fighter-type character will be the strongest in any party, but as you level up and grow stronger very little is added to the base kit aside from linear power growth. Meanwhile a Level 1 Mage-type character will start off with no defense and one or two relatively weak spells, but if you can survive long enough to gain levels you'll find your usefulness and versatility increasing exponentially as you learn more powerful spells.
In other words, Fighters start the game as good combatants and end the game as great combatants. Mages start the game as conjurers of cheap tricks and end the game as harbingers of the apocalypse.
Meanwhile the Thief is busy picking your pocket and slipping you poison.
Most video game protagonists in non-RPG games tend to be either Fighter or Thief based, though Mage-like abilities aren't uncommon.
So, dear readers, which of these archetypes tend to speak the most to you?