See Chapter 6: Customization Options in the 5e Core Rules for official rules on characterization.
The combination of attribute scores, race, class, and background defines your character’s capabilities in the game, and the personal details you create set your character apart from every other character. Even within your class and race, you have options to fine-tune what your character can do. But a few players — with the GM’s permission — want to go a step further.
This section defines three optional sets of rules for customizing your character: birthsigns, multiclassing and feats. Multiclassing lets you combine classes together, and feats are special options you can choose instead of increasing your attribute scores as you gain levels. Your GM decides whether these options are available in a campaign.
In Tamriel, a birthsign is the constellation under which a person is born. Each bestows upon those born under it unique magical powers—either passive or active—and may be perceived as either a "blessing" or a "curse".
Multiclassing allows you to gain levels in multiple classes. Doing so lets you mix the abilities of those classes to realize a character concept that might not be reflected in one of the standard class options.
A feat represents a talent or an area of expertise that gives a character special capabilities. It embodies training, experience, and abilities beyond what a class provides. See the feats in the 5e Core Rules for more information.
Factions & Guilds
The Heroic Chronicle is a system that allows players and Game Master to work together to build a compelling character story within the Elder Scrolls universe. It even allows characters to gain additional proficiencies, magic items, spells, or feats before the campaign begins.