Traits

The Trait system was a feature of Diablo III introduced during BlizzCon 2010. Traits were passive skills that allow character customization and diversifying builds. They altered core character attributes and, to some extent, even mechanics of the class. They were replaced with Passive Skills before the game was released.

Overview
Traits were mostly unique to character classes, with some overlap. They were designed specifically to replace the statistics from Diablo II, as this system has become outdated and didn't allow genuine character customization. Since active skills and passive skills (traits) have now been completely separated, players no longer need to feel like they are 'sacrificing' points in order to get permanent benefits and not spectacular skills and abilities.

Traits let players diversify their builds and create characters they want. For example, if a player wished to play a strong and tough, they could choose traits like Legendary Might (increases Strength) or Iron Skin (increases Armor). Alternatively, if a player wanted to build a more damage-oriented Berserker Barbarian, they could choose traits that increase attack rate or power of debuffs on their enemies.

Traits were gained every other level. Every class had roughly 30 traits, where player could spend between 1-5 points in them.

Examples of Traits
Ball of Lightening (Wizard)

A shocking defense will make enemies ponder the wisdom of their assault.

Rank 0/1

Periodically shocks a nearby enemy for 1-120 electrical damage.

Inner Rage

"While most orders teach the merits of calming the seas of the soul, the guardians of Arreat have embraced the raging inner storm." - Chronicler Ravgres

Rank 0/5

Reduces the rate of Fury lost and increases Fury gained for hitting the same target.

Prismatic Cloak (Wizard)

An icy mist that freezes to the bone, the low hum and spark of electricity in the air… even touching a Wizard can have dire consequences.

Rank 0/3

Increases the effects of Ice Armor and Storm Armor by 100%.