Quests

Quests are missions or tasks that players are given throughout each installment of the Diablo series, and which they can complete for a reward. Quests also usually serve to advance the game's plot or expand upon the elaborate storyline.

Most quests are prompted by NPCs; some however can also be prompted by travelling into a new area or reading a tome. If prompted by an NPC, he or she will have an "!" above his or her head and move towards the player to indicate that they have a quest. Clicking on the NPC will open a dialogue in which players can see what he or she wants.

The quest log (accessed by pressing Q) assists players in quests by reminding them of objectives and appearing when players are near an objective concerning the quest. The quest log also saves dialogue from NPCs that give out useful information regarding the missions.

The rewards yielded from completing quests can range from additional Skill Points, Stat Points, an item, or access to later parts of the act. The last quest of an Act always grants access to the next Act or Difficulty.

Diablo I quests
In Diablo I, the quests are a series of missions (fewer in multi-player) on which the character is sent, and which offer advantages when completed. None of them need to be completed, but all add background detail and most give valuable rewards (even if only when reselling). Though there is only a finite number of unique quests, each new game generates a random selection of quests. Therefore if players create a new game they might encounter different quests.
 * Diablo quests
 * Hellfire quests

Diablo II quests
In Diablo II, the quests are a series of missions of which most are integral to proceeding in the single-player game. For example, without the Cube, the Heart, Eye and Brain, and the Flail, the single-player character cannot get beyond the Third Act City. However, in multi-player, an advanced character can open a town portal from a waypoint beyond the blocked part, enabling a less-experienced player to bypass the quest entirely. Each Act has 6 quests, with the exception of Act IV, which has only three. Certain quests can be bypassed as they require finding a specific non-essential item, such as the Tools of the Trade Quest, but skipping or failing to complete these quests often result in losing out on permanent bonuses.
 * Diablo II quests
 * Diablo II: Lord of Destruction quests

Diablo Immortal quests

 * Diablo Immortal quests

Diablo III quests
Diablo III promised to bring more interactive quests that will be much more rewarding. They tie in closely to the idea of randomness - when replaying the game, the player will most likely get to find quests that were not available to them before.
 * Diablo III quests
 * Diablo III: Reaper of Souls quests
 * Events