Difficulty

There are six different quest difficulty settings in DDO. Starting from easiest, these are Solo, Casual, Normal, Hard, Elite, and Reaper. In addition, game differentiates between three tiers of play: Heroic (up to level 20), Epic (21-30), and Legendary (level 31+). A combination of difficulty setting and game tier defines the actual difficulty, for example Heroic Elite or Epic Hard.

Higher settings are more challenging but often more rewarding in terms of Experience, Favor, and loot from within the quest. Not all quests are available at all difficulties. Most players would consider Epic Casual and Epic Normal to be much easier than high level quests on Heroic Elite difficulty. The "Epic" in epic difficulties only signifies that it is for a significantly different level range of characters, for quests with both a heroic and an epic version.

Initially, only Solo, Casual and Normal difficulty are available to Free To Play and Premium players who have never completed that quest before. F2P & Premium characters who have undergone True Reincarnation can open heroic quests on Hard difficulty after the first reincarnation. Characters with two past lives can open Elite or Reaper. VIP subscribers can open quests on Elite. Completing a quest on any difficulty unlocks all difficulties up to and including one setting higher. (See below)

While in a party, the first player to enter a quest can usually choose from any difficulty that any of his teammates has unlocked through completion of the quest. This does not work if the teammate is simply VIP or has undergone True Reincarnation; in such a case, that teammate must enter the quest first in order for the others to "follow" in. Additionally, this may not work if an NPC teleports you into the quest, such as with Gladewatch Outpost Defense.

Quests which features Solo difficulty are now Solo-ONLY as of Update 3. This is because Casual replaced the Solo setting as the lowest setting on all quests except those that featured only Solo and added Casual to all quests that originally featured nothing below Normal.

Solo

 * Solo difficulty is only available for a small amount of selected solo-only quests.
 * There may be fewer and/or smaller encounters than Normal (Though you can no longer run these quests on normal to tell anymore)
 * The quest's level may be reduced by 2 levels for purposes of generating chest loot. Rewards from the quest's giver are unaffected and still rewarded as if you ran the quest on elite.
 * Enemies and traps are lowered in difficulty.
 * Dungeon Scaling does not apply. The dungeon is already easier due to other factors.
 * Enemy misses become Grazing Hits on raw die rolls of 19.
 * Some enemy special attacks, like scorpion poison, have no effect.
 * Rest shrines can be used every 5 minutes.
 * You must solo. You cannot have teammates or hirelings, although artificer and druid pets, as well as summoned monsters, are allowed.
 * You must solo. You cannot have teammates or hirelings, although artificer and druid pets, as well as summoned monsters, are allowed.

Casual

 * Dungeon Scaling is in full effect, and scales the dungeons more heavily than standard normal scaling.
 * Favor is 1/2 of Normal, dropping fractions.
 * Main quest XP is roughly 0.45 to 0.5 × Normal.
 * All enemy encounters are of the same size and CR as normal, and have the same abilities, but they are heavily scaled down as casual is heavily adjusted down by Difficulty Scaling.
 * The quest's level is reduced by 1 (if possible) for purposes of generating chest loot and comparing against the party's level for XP adjustment. Rewards from the quest's giver are unaffected.
 * Enemies and traps are scaled down in difficulty "by about two levels" according to an interview with Community Representative Tolero.
 * Rest shrines can be used every 5 minutes.
 * There is no XP penalty for re-entering the dungeon, though the XP bonus for not re-entering at all can still be lost.
 * Some chest loot that is guaranteed to appear at other difficulty settings has only a chance of appearing. On average the droprate is reduced by 50%.
 * Optional XP bonuses are worth double their normal values.
 * Casual is intended for solo players, or groups looking to enjoy the storyline while not worrying about the combat.

Normal

 * Dungeon Scaling is in full standard effect.
 * Enemy misses become Grazing Hits on raw die rolls of 17-19.
 * Rest Shrines can be used every 15 minutes.
 * Most normal difficulty dungeons are most evenly balanced against a party of four players. However most quests are also designed to be soloable on normal as well due to scaling. If it's a raid, 12 players are still recommended, but often not required.
 * Normal difficulty is intended to be the default choice for the large majority of players looking for a balanced experience.
 * Monster Damage Reduction, at their best, block only 50% of your damage instead of their true value

Hard

 * Dungeon Scaling is in effect, but has less of an impact than Normal.
 * Favor is 2 × Normal.
 * Main XP is roughly 1.05 to 1.08 × Normal.
 * There may be more and/or larger encounters than Normal.
 * Enemies are always a higher CR, and have far higher statistics designed to challenge more prepared parties.
 * Enemy spell casters often have more and higher level spells.
 * Monster Damage Reduction, at their best, block only 75% of your damage instead of their true value.
 * For example: If your attack deals 16 damage, but the monster has DR 15/-, your attack still deals 4 damage. You can see it better against the DR 100 monsters: ghostly skeletons in Delera's and gargoyles in Stone Form.
 * The quest's level is increased by 1 solely for purposes of generating better chest loot and comparing against the party's level for XP adjustment. Rewards from the quest's giver are unaffected.
 * Traps are greatly increased in difficulty, in terms of damage dealt, save DC and skill DC needed to disable them. They are intended to challenge decently-geared rogues of appropriate level.
 * Hidden doors and Lock DCs sometimes scale up a few points.
 * Enemy misses become Grazing Hits on raw die rolls of 15-19.
 * Rest Shrines can only be used once. Some quests have fewer shrines when compared to Normal.
 * Hard is intended for full, well-balanced groups of 6 players, or 12 if it's a raid.
 * Free to play and premium players cannot open a quest on hard unless they have already completed it on Normal or higher difficulty, or they underwent True Reincarnation at least once. They can use from the DDO Store to bypass this limitation.

Elite

 * Dungeon Scaling is in effect, but has less of an impact than Normal/Hard.
 * Favor is 3 × Normal.
 * Main XP is roughly 1.10 to 1.16 × Normal.
 * There may be more and/or larger encounters than Hard.
 * Enemies are always a higher CR than on Hard, and have far higher statistics designed to challenge very well seasoned veteran parties.
 * Enemy spell casters often have more and higher level spells and sometimes even gain the Maximize feat.
 * The quest's level is increased by 2 (compared to Normal) for purposes of generating chest loot and comparing against the party's level for XP adjustment. Rewards from the quest's giver are unaffected.
 * Traps are massively increased in difficulty, in terms of damage dealt, save DC and skill DC needed to disable them. They are intended to seriously challenge decently-geared rogues of appropriate level.
 * Hidden doors and Lock DCs sometimes scale up a few points.
 * Difficulty Scaling is in full effect, but has less effect than Normal/Hard, unless the quest is a raid.
 * Enemy misses become Grazing Hits on raw die rolls of 13-19.
 * Rest Shrines can only be used once. Some quests have fewer shrines when compared to Normal/Hard.
 * Certain quests will feature more difficult unique required objectives only on elite. A good example is In the Demon's Den. See its quest page for details.
 * Elite is intended for full, well-prepared, well-balanced groups of 6 players, or 12 if it's a raid.
 * Free to play and premium players cannot open a quest on elite unless they have already completed it on Hard or higher difficulty, or they underwent True Reincarnation at least twice. They can use from the DDO Store to bypass this limitation.

Reaper difficulty
Reaper difficulty was introduced in Update 34 and aims to challenge the most skilled and geared players. Reaper counts as Elite for most purposes, including Favor, Bravery bonus, and Saga rewards. Note that Bravery bonus only applies to regular experience. Reaper experience is calculated from the base quest level and has a significant and increasing penalty for every level above base. For example if running a Reaper difficulty quest at base plus two levels (the standard Bravery bonus level) there is a 50% penalty applied to reaper experience. See separate article for more information.

Unlocking higher difficulties
A VIP character or a character that has undergone 2 Reincarnations (any of Heroic True Reincarnation, Racial Reincarnation, Iconic True Reincarnation) can select any difficulty from the quest panel. A character that has undergone 1 reincarnation can only open up to Hard difficulty. Other characters that wish to open hard and elite/reaper need to complete the adventure on the immediately lower difficulty (normal and hard respectively). Having completed elite/reaper or hard difficulty unlocks all difficulties for that quest. This means that a normal player playing alone needs to complete the quests 3 times to get the maximum favor: normal, hard, elite. You can also open a difficulty by using a or  from the DDOStore.

Most players want to do elite on their first run. That is where parties come in. If the adventure is already opened on a higher difficulty by a party member that can open it, you can enter it at that difficulty thus bypassing your inability to open higher difficulties than the ones you have unlocked. The ways to enter a quest on a higher difficulty are the following:
 * Have someone in the party that can somehow open a high difficulty (VIP, Legend status, unlocked via play, used a difficulty unlock item from the DDOStore) enter the quest first. Since all party members enter the same instance, they all enter that difficulty. Even if that player leaves the quest (or the party), the difficulty will remain set as long as the adventure doesn't reset (which can happen if 5 minutes pass without someone inside, if the leader resets it from the quest panel or if the party is disbanded and noone is inside the quest).
 * Have someone in the party that has unlocked a high difficulty by having played the quest before on hard or elite/reaper and has gotten the quest again from the quest giver or by quest sharing. Other party members can then also select the higher difficulties that this party member has unlocked. This way of opening has the benefit that the opener doesn't need to enter the dungeon thus allowing the opener to be any level without applying any penalty to the dungeon instance.
 * If you are using an over-level opener that has not yet run the quest, and does not want to run it, proceed as follows:
 * Opener must be the party leader. Enter on elite.
 * Favor-seeking character opens the quest entrance window, but does not enter.
 * Opener recalls and then resets the quest.
 * Favor seeker uses the window to enter on elite.

Epic difficulties

 * Epic difficulties are only available at level 20 and above.
 * The end chests of quests in Eberron drop Tokens of the Twelve (except in Epic Casual).
 * Unlike Heroic Normal/Hard, enemy DR in Epic Normal/Hard quests is not percentual.
 * In Epic Hard and higher difficulty settings, enemies have Epic Ward. Orange named enemies gain Deathblock. Charm spells have significantly shorter duration.
 * Some quests have fewer shrines when compared to their heroic version.
 * Epic Resilience: Monsters in Epic Elite get a special bonus to save against magic, and only magic, while they are healthy. This doesn't affect non-magical effects. There's a similar but smaller bonus on Epic Hard.
 * "Magic" in this case means all spells, and possibly some other abilities/effects that we've explicitly marked as magical over the years.
 * This starts at +6 to saves, drops to +4 once the monster is hurt at all, and then to +2 when between 50% and 75% health. Below 50% health they receive no bonus.

Raids
Although raids aren't a difficulty setting, they do impose their own special rules much like difficult settings do. Here's a short list of some of them:
 * Casual difficulty is never available for raids, they are intended to be challenging adventures not suited to casual play. Normal, Hard, Elite, and Reaper is available for all raids.
 * Dungeon Scaling is disabled, regardless of quest difficulty.
 * Hirelings may not be summoned in raid dungeons.
 * Many special items from the DDO store are disabled while in raids, including:
 * Summoned Repair Shop
 * Summoned Rest Shrine
 * Rest of the Eladrin statuette
 * Resurrection cakes of any type
 * Several raids feature some form of lock out. Either early on the raid, just before the main boss fight, or both. This is to prevent you from releasing and coming back in to try again without restarting from the beginning.

Epic history
Main article - Epic (This has NOT been fully updated since level 21-25 and Epic Destinies were implemented.)
 * Enemies, traps, bosses and sometimes even objectives are massively scaled up, see main article for full details.
 * Only level 20-25 characters may enter.
 * Enemies have Epic Ward.
 * Orange named enemies have Deathblock.
 * Enemy misses become Grazing Hits on raw die rolls of 13-19.
 * Rest Shrines can only be used once. Some quests have fewer shrines when compared to elite.
 * Epic was originally intended to be a massive step above elite quests, and purely for the "best of the best". These days it's been tweaked downwards to just slightly harder then a level20 elite quest would otherwise be, and thus very doable by a wider range of players.