Talents are, essentially, your characters skillset. They are what your character is best at. This does not mean your character is incapable of doing things other than their own talents, however - and you can, in fact, earn talents in-game. That, however, takes a lot of time and practice.
So you must choose your starting FOUR talents (or FIVE, if you have 8+ Intelligence) very wisely, as they'll be all you have for quite some time.
You may choose from any combination of categories; you may also create your own (more on that toward the end of this post), although you are encouraged to use existing talents. As mentioned, your choices here are very important in defining your character's abilities and skills. If you attempt to perform an action in which you do not have a talent, you will most likely fail.
Each talent is attached to an attribute (listed in parentheses). The higher the attribute, the better your skill with that talent will be.
The following is the full talent list, each under different categories:
Charisma (Spirit) - You have a natural charm that lets you more easily influence people, and inspire them to fight for you in battle.
Diplomacy (Intelligence) - You are skilled in the art of persuasion, haggling, and making deals. Useful for political leaders and merchants.
Intimidation (Strength) - You can be pretty scary, coercing people into seeing things your way, or intimidating enemies into backing down from a fight.
Education (Intelligence) - Required in order to be able to read. Your character has a solid knowledge of history, geography, and mathematics, and the ability to read and speak one language of your choosing.
Therefore, if you choose Education, you must also choose a language in which you are educated, and you will gain literacy in this language (and the ability to speak it, if you do not have that already).
Remember, it is assumed, unless the player states otherwise, that ALL player characters know how to speak Common Imperial, but not how to read it. If you want to be able to read it, you must choose it as your language for your Education talent. You do not receive any languages for free.
For a full list of the languages available, see this post.
Multilingual (Intelligence) - Your character is not educated enough to be literate, but you know how to speak more languages than others. This is based on your Intelligence score; for every 2 points of Intelligence over 5, you may choose another language to know how to speak.
In other words, if you choose Multilingual and your character has an Intelligence score of 5, you may choose one additional language.
If you choose Multilingual and your character has an Intelligence score of 7, you may choose two additional languages.
If you choose Multilingual and your character has an Intelligence score of 9, you may choose three additional languages.
And so forth. For a full list of the languages available, see this post.
Arcane Lore (Intelligence) - Useful to many different individuals, including Magi and Inquisitors, and anyone who wishes to fight mages. Grants knowledge about magic and ancient legends and artifacts. Grants magi knowledge of additional spells and helps them control their power, but their raw elemental attacks will be slightly less powerful.
Divine Lore (Spirit) - Useful to many different individuals, including priests and Templars, and anyone who wishes to fight demons and undead. You know a great deal about your favored god, their ways and tenets, how the cosmos works in general, and you have extensive knowledge of demons, undead, the holy, and the unholy. If you have Divine magic, your Divine magic is more powerful, and you know a wider variety of spells than most.
Forbidden Lore (Intelligence) - Useful to those who want to use Demonic magic and communicate with demons, or simply better understand demons and the undead. Similar to Divine Lore, but not for the same purpose or through the same channels. You know a great deal about the forbidden subjects of demons, dark magic, and undead. You know how to communicate with demons, how they work, their tricks, and how to make deals with them. You understand demonic rituals and how to summon a demon. You also know how to create soulstones. If you have Demonic magic, your Demonic magic is more powerful, and you know a wider variety of spells than most.
Monster Lore (Perception) - A very specialized skill mostly useful for Venatori and anyone who wishes to hunt monsters. Grants some knowledge about monsters, how to track them, how to identify them, and their weaknesses.
Balanced Soul (Spirit) - Useful to many different individuals, including shamans, druids, and anyone who wishes to have a powerful will. You have achieved a balanced soul, and therefore you are very resistant to outside influences, from simple annoyances, to torture, to curses or other forms of magic. If you have Spiritual magic, your Spiritual magic is more powerful, the spirits will aid you more readily, and you know a wider variety of spells than most.
Survival (Constitution) - You know how to live off the land, treat wounds, navigate, and do what it takes to survive. You're also not a bad cook.
Noble Combat (Strength) - You are highly trained in the types of combat befitting the nobility, including horseback combat, jousting, and dueling. You are good with most types of melee weapons, but especially swords.
Martial Combat (Strength) - You are highly skilled in melee combat on foot, either alone or as part of a group. You are good with a wide variety of melee weapons as well as throwing spears and axes. You are less skilled fighting on horseback.
Brawler (Strength) [as suggested by Sareth] - You are a simple person, and you prefer simple weapons. You are a master of unarmed combat, and are best at defending yourself with the weapons nature gave you—your hands and feet (and claws, if you've got any)—although you are also adept at the use of simple weapons like quarterstaves and cudgels.
Finesse Combat (Agility) - You prefer to fight using your agility rather than your strength. You are skilled with a variety of weapons, so long as they are not too heavy and slow. You prefer to fight alone, giving you room to move, and you may employ unconventional and sometimes underhanded methods.
Marksmanship (Perception) - You are a great aim with ranged weapons, especially bows and crossbows, and can hit targets both nearby and at great distances.
Subtlety (Agility) - Disguise, sneaking, creating distractions... that sort of thing is right up your alley. You also do more damage when taking your opponent by surprise or attacking when they are off-guard.
Thievery (Perception) - You are good at stealing things. You can pick locks, spot and disarm traps, size up good robbery targets, and pick pockets (best to also have Subtlety for that last one).
Please note that Errant does not have a robust gathering and crafting system. You are allowed to occasionally create your own gear, if you have the materials, and you can repair things related to your skill. There are improved versions of most skills, but they are restricted.
Herbalism (Intelligence) - You are an expert in the use of herbs and brewing of potions of a wide variety of types and applications. You're also a pretty good cook.
Venator Herbalism (Intelligence) (Venatori only) - You are not only an expert in herbs and potions, but you have used potions so much that you no longer feel many negative effects from their use. You also know how to brew some of the rarest and most valuable of potions, given you have the right ingredients.
Blacksmithing (Intelligence) - You are skilled in the art of blacksmithing, forging metal tools (such as horseshoes), weapons, and armor, if you have the proper tools.
Dwarven Blacksmithing (Intelligence) (dwarves only) - You are a master of blacksmithing - you know not only how to work with ordinary metals (with proper tools, of course), but you also know the secrets of how to forge metals mined by dwarves: deepgold, deepsilver, and even void iron. Be very careful with these talents, however - if you sell armor and weapons of such materials without the Iron Gauntlet's permission, you could be in serious trouble.
Jewelcrafting (Intelligence) - You are good at the meticulous art of jewelcrafting: making things such as amulets, rings, torcs, and more. You know how to manipulate the finer metals, such as copper, gold, silver, and bronze.
Dwarven Jewelcrafting (Intelligence) - You are a master of jewelcrafting - you know not only how to work with ordinary metals, but also how to craft jewelry from deepgold, deepsilver, and even void iron.
Leatherworking - You know how to craft leather armor and equipment, including saddles, bags, and more.
Elven Leatherworking (Intelligence) (elves only) - You are a master of leatherworking, and you know how to create the finest leather armor possible, thanks to Elven secrets.
Tailoring - You are a good tailor; you know how to work with cloth and create lovely clothing.
Woodworking (Intelligence) - You know how to work with wood to create various tools and weapons - everything from bows and arrows, to fixing wooden carts, to carving flutes.
Elven Woodworking (Intelligence) (elves only) - You are a master of woodworking, and you know not only how to make the simple things, but also masterful Elven bows, and more.
You are allowed to create your own, custom talents for your character. However, they must fall into one of the existing categories.
If you want to suggest a talent that is not in one of the existing categories, you may still propose it, but it is less likely to be accepted.
To request a custom talent, simply use the Special Permissions thread to request a custom talent, explain what exactly it would do for your character, what it is called, what category it falls into, and what its governing attribute is.
Acquiring Talents In-Game
For more info on this, please see the help thread devoted to it.