An Eternal Conflict...
As you venture through Maps, you'll occasionally encounter Timeless Monoliths.
Interacting with one of these Monoliths begins an encounter with forgotten, time-lost armies of the past. The encounter comes in two phases. First, you have a limited time to free as many frozen monsters as possible by 'killing' them. And second, you have to actually fight the monsters you freed.
In addition to the rank and file, there will be chests (which still have to be attacked and 'freed' but not fought afterward) and special monsters marked with symbols. Defeating these will yield specific kinds of loot, depending on the symbol displayed.
This monster's symbol indicates it will drop an Essence item when defeated...
...while this chest holds a Unique item.
In general, the best rewards are found at the far edges of the two warring armies (in other words, from the monolith, you'll want to head directly into one of the two armies in a direction perpendicular to the lines of enemies). You'll often find a special boss (a "General") or a very large chest there with lots of Timeless Splinters (see below for more on these).
Legions drop special items called Incubators. Incubators are consumable currency items that you can apply to equipment, causing an item to drop after some very large number of kills with that item equipped.
When an incubator is close to being filled up, it'll show up on the right side of your screen, the same way a gem close to leveling would. Once it's full, its associated item just shows up like any other drop. Once the drop appears, the Incubator effect vanishes from the equipment it's attached to, so Incubators only get you one drop of their associated item. Think of them as just "more loot, but delayed".
Splinters, Emblems, and Timeless Conflict
There are five armies locked in the timeless conflict, each of which appears to have an associated color: Eternals (white), Karui (orange), Maraketh (yellow), Templar (green), and Vaal (red). Each is a major faction from Wraeclast's history.
Defeating enemies and looting chests associated with a particular army can drop Timeless Splinters associated with that army. Collecting 100 of these combines them into a Timeless Emblem. Two or more different Emblems can, in turn, be inserted into the endgame Map Device to open portals to the Domain of Timeless Conflict, where the armies you've encountered are locked in eternal battle, led by their respective generals. This is an endgame boss encounter; two-emblem Domains are comparable to yellow-tier maps, three-emblem ones to red-tier maps, four-emblems harder still, and five-emblems harder even than that. More emblems yield more opportunities for loot, but only highly geared players should attempt four- or five-emblem runs.
Completing the Domain of Timeless Conflict can drop special Timeless Jewels. You can use one, and only one, of these Jewels to modify your Passive tree significantly.
Each Jewel is affiliated with one of the five factions, and with one of three major characters from that faction. When socketed, the Jewel modifies passives within a large radius, changing their effects. The exact changes depend on the number displayed on the Jewel, and are different from one Jewel to another. The exception to this rule is its changes to Keystones, which are determined by the name displayed on the Jewel. For example, an Eternal Empire version might say "8,452 Coins Commissions to Commemorate Chitus". The 8,452 determines its minor effects, and "Chitus" determines that it will convert Keystones into the special keystone Supreme Ego.
There are 15 special Keystones in all, most with highly specialized effects. The various factions also have a collection of minor effects on nodes:
- Karui jewels add Strength to minor passives, and add random bonuses to notables.
- Maraketh jewels add Dexterity to minor passives, and add random bonuses to notables.
- Vaal and Eternal jewels replace normal minor passives and notables with completely new and highly random effects.
- Templar jewels replace normal minor passives with notes that grant 10 "Devotion". They then replace notable passives with bonuses dependent on your total amount of Devotion.