Reaper difficulty

Reaper Difficulty or Reaper Mode is the highest difficulty in DDO introduced in Update 34. This game mode has ten sub-difficulties, known as "skulls," that can further increase the challenge rating. In this difficulty, many things are changed, so proceed with caution! Most notably, self healing in reaper mode is significantly reduced. Players will also find that they do less damage and take more of it, including attribute damage. There are special monsters only found in this game mode known as Reapers (see below) which have dangerous, powerful abilities. As a reward for braving this difficulty, players will earn more experience points, more named treasure (with increased chances Mythic Bonuses and exclusive chances for a "Reaper Bonus"), and Reaper Experience, which unlocks Reaper enhancements and cosmetics.

Update 34 Release Notes:
 * Reaper Difficulty offers a new challenge for the toughest adventurers! Reaper difficulty can be selected from the quest portal UI for many quests and raids throughout the game. When you select Reaper difficulty, there is also a drop-down list of between one and ten Skulls, which affects quest/raid difficulty and reward. Special Reaper Bonuses can be found on items acquired in Reaper Difficulty, there is an increased chance to get named items, and you'll earn Reaper Experience. Reaper XP will award a Reaper Point at certain thresholds that can be spent on abilities in a special Reaper benefit tree, among other things! Warning: Reaper difficulty is meant for players who enjoy a serious challenge. You have been warned!

Game mechanic
Reaper is the fifth difficulty setting for quests, above Elite. Further, Reaper allows players to decide how much of a challenge they want by selecting an appropriate number of "skulls" (1 Skull = easiest vs 10 Skulls = hardest), adding further difficulty if the player so chooses.

A quest can be opened on Reaper difficulty by any character who can open Elite difficulty. This means VIP accounts can do so at any time, but Free-to-play and Premium characters must have already completed the quest on Hard, or have reincarnated at least twice (same as opening for Elite difficulty), or are in a party with a member who can open on Elite.

The following applies to reaper mode:

Monsters are stronger

 * Monster damage is increased.
 * Many/all monsters are Champions, often with multiple buffs. The strongest and most dangerous of the three tiers of champions, red-crown, is found in Reaper difficulty (and nowhere else).
 * All monsters receive bonus to saving throws ( have shown a +1.5 to saves per skull)

Players are weaker

 * Player damage is reduced.
 * Self-healing is dramatically weaker (60% in 1 Skull; an additional 4% per skull, up to 96% reduction for 10 Skulls.) (This applies also to Lesser Restoration pots, making them fairly ineffective for restoring ability damage.)
 * As of U40, damage and healing values now have a minimum value of one due to Reaper scaling. If Reaper scaling would reduce a value for damage or healing that is above zero to zero, then the value will now be at least one.
 * It is unclear is this includes Ability damage to enemies.
 * It is unclear is this includes Ability damage to enemies.


 * Crowd control effects have reduced duration (If a CC is reduced, it is reduced to 6 seconds minimum. It keeps the shorter, single target CC relevant, particularly tactical stuns from enhancement trees.) On reaper 10, cc is reduced by a factor of ~8.5.
 * Death timer: Dead players cannot be raised for some time (6 seconds per skull?). Being returned to the soulstone because of distance will reset the timer. NOTE: Will also reset raid death timers.


 * Incorporeality and Concealment (Blur/Displacement/...) have reduced effect.

Lockout

 * Characters cannot enter a quest on Reaper Difficulty if they are more than four (Heroic) / six (Epic) levels over the level of the dungeon or raid (based on Normal difficulty, not the modified level on Elite Difficulty).
 * Characters also cannot enter a Reaper Dungeon if they are Epic Level and the Dungeon is not.
 * Reaper dungeons lock their instance when a player leaves. No other player may enter (or reenter) the instance again.
 * Tip: Dungeon does not lock if you close DDO (for example using Alt+F4) and party leader dismisses you while linkdead.

Other changes

 * Defeated enemies can drop Lost Souls. One character in a party can consume them to recharge some of their spell points. The amount of restored spell points depends on quest level and is equal to 5 * (base quest level + 3)
 * Hirelings cannot interact with the Lost Souls, and so cannot regain SP in this method.
 * Interacting with Lost Souls breaks Invisibility, Stealth and Ki Finishers, much as interacting with a lever does. May or may not be WAI.
 * Since Update 42 Patch 4 the appearance of Lost Souls scales with party size and Reaper skulls. Fewer souls appear for smaller parties and on lower reaper levels.
 * Upon entering dungeons on Reaper difficulty, characters are restored hit points and spell points equal to what's granted by their reaper enhancements.

Experience
Completing quests on Reaper difficulty provides more Heroic or Epic experience points (XP). Reaper quests award both regular experience and Reaper experience (RXP).
 * Base XP is the same as Elite
 * First-time completion bonus for Reaper difficulty is +95%.
 * Bravery Bonus for Reaper difficulty is +100% (same as Elite).
 * Sagas progress as on Elite.

Reaper experience
In addition to the regular heroic or epic experience (XP), completing quests on Reaper difficulty yields Reaper experience (RXP). ''n.b. RXP is only awarded when at least ten enemies are defeated in a quest. Killing 9 or fewer enemies still gives regular XP with bonuses for Reaper difficulty, but yields zero RXP.''
 * RXP grants you Survival Points (aka Reaper enhancements)
 * RXP unlocks Reaper vendors (see below)

Starting at Level 4, Survival Points can be invested in any of three Reaper enhancement trees. There are 3 trees available, which are essentially: These work in a similar manner to enhancement trees, but are only actively applied to a character while within a quest on (any) Reaper difficulty. As with enhancement trees, these points are never actually spent, so a character can pay PP to re-allocate them as desired.
 * melee/ranged - Dread Adversary
 * casting - Dire Thaumaturge
 * defense - Grim Barricade

The base RXP reward (displayed at the top of the experience log) is the based on dungeon level, the number of skulls selected and the quest length.
 * Base RXP = (50 + 3 * (quest level on Normal) * (number of skulls)) * Length Bonus (0.8 (short), 1 (medium), 1.2 (long), 1.4 (very long))

The final RXP total (displayed at the bottom of experience log) is modified for the following reasons:
 * deaths
 * number of enemies killed
 * number of traps disarmed
 * number of breakables destroyed
 * over-level penalties
 * power leveling penalties
 * first time bonuses
 * XP tomes

Regular experience boosts such as Heroic Inspiration, VIP boost, guild airship buffs, and experience elixirs also increase RXP granted.

A character continues to acquire RXP when capped for heroic or epic experience (i.e. after reaching the XP banking cap or level cap, quest completions will continue to award RXP).

The following bonuses don't apply to RXP: RXP persists through reincarnation, but must be re-allocated once a character hits Level 4 (or higher).
 * Bravery bonus ,

See also:
 * Reaper enhancements/XP per Point
 * Reaper enhancements

Overlevel penalties
There is an RXP over-level penalty. Since Update 42 Patch 4 the penalties are the same as for regular XP. Compare the maximum character level in the group to quest level on Elite:
 * +1: no penalty
 * +2: -10% (this is the highest possible penalty in heroic quests, because higher level characters cannot enter)

There are no overlevel penalties in epic, just the six level lockout. 

Note: The over-level penalty also applies to hirelings, including gold seal hirelings. A particularly punishing example is summoning a level 20 hireling, such as the Onyx Panther (ML18) in heroic reaper. This prevents all RXP.

Quest length multiplier
As of Update 34 Patch 2, RXP is modified based on the length of the dungeon/raid:
 * Short - 0.8
 * Medium - 1.0
 * Long - 1.2
 * Very Long - 1.4

CR 30 dungeons
RXP is doubled in base level 30 or higher dungeons.

Reaper Vendors / Rewards
Reaper Vendors are available in the Hall of Heroes. They sell Creature Companions and potions that grant special cosmetic feats.

Very high totals of Reaper Experience are rewarded with special cosmetics or a creature companion. There are three different vendors, each with a different Reaper Experience requirement that must be met before they will talk with you. The platinum costs are high; buy these items when you have high haggle.

Note that the eyes (and wings? I don't know, needs confirmation) last for a single life and need to be purchased again after you TR.
 * Raven Queen Messenger (625,000 Reaper Experience)
 * Cosmetic eyes, base cost 1M Platinum.
 * Raven Queen Augur (2,500,000 Reaper Experience)
 * Reaperling creature companions
 * Raven Queen's Herald (5,625,000 Reaper Experience)
 * Cosmetic wings

Items
The contents of chests and end-loot, including the presence of Named Items, have (slightly) improved chances of better results on Reaper difficulty, often with higher reaper difficulty (aka "most skulls") resulting in slightly higher percentages of that better result.

Benefits
 * 1) Higher treasure level in randomly generated loot
 * 2) More Monster Champions = more Mysterious Remnants
 * 3) Increased chance of dropping named items: +1% per skull level.
 * 4) Increased chance of named items having Mythic bonus.
 * 5) Chance of named items having Reaper bonus.

Notes
 * Each of these chances increase in likelihood for each reaper skull.
 * Applies to static named items from quests. Crafted items or end rewards don't have this benefit.
 * Some dev quotes available here.

An item with Reaper bonus gains one of the following:
 * Reaper Ability Boost: Provides 2 Reaper Bonus to all Abilities (found on helmets only)
 * Reaper Power Boost: Provides 3 Reaper Bonus to Melee, Ranged and Spell Power Ratings
 * Physical Resistance Rating +3
 * Magical Resistance Rating +3

Non-reaper quests
Certain quests are not available on Reaper difficulty:
 * Korthos quests
 * Solo-only quests
 * Protect Baudry's Interests
 * Stop Hazadill's Shipment
 * Tangleroot Gorge quests
 * Mask of Deception
 * Precious Cargo
 * Heroic and Legendary Hound of Xoriat  (Again available with Update 42 Patch 4 Release Notes)

Development
Prior to Lamannia Update 33, Reaper Mode was a whiteboard idea for a dungeon difficulty harder than elite in development internally and mentioned to the Player's Council. Some of its simple text leaked onto the Lamannia preview server while Update 27 was being previewed.