Expedition introduces the Kalguuran expedition, who came to Wraeclast to excavate their ancestor's lost settlements. Using explosives, the player sets them around the expedition site to unearth the monsters or treasure hiding underneath. After recovering Artifact pieces from the Expedition, you can barter or gamble with them for items. You can encounter Expeditions as soon as you reach Act 6 in the Campaign.

The Expedition mechanic also introduces a special defense stat called Ward, which shields damage on the next hit they take and replenishes after a 5 seconds delay which cannot be interrupted. Expedition Monsters can use this new defensive mechanic, but players can also play around it with new item bases that can drop from Expedition.

All Expedition related items (Artifacts, Vendor Refresh Currencies and Expedition Logbooks) can be stored directly in the Expedition Locker in your Hideout. Important: Artifacts which are used to trade with the Kalguuran cannot be traded.

Dannig
He is used to open Expedition Logbooks in your Hideout. He sells Artifacts for the other three NPCs in exchange for Sun Artifacts. His inventory contains Artifacts for the other three NPCs with better exchange rates, Vendor Refresh Currencies as well as Expedition Logbooks sometimes and is reset through Burial Medallions.

Gwennen
She sells unidentified equipment, which reveal their rarity and mods when purchased. She accepts Broken Circle Artifacts and Astragali to refresh her inventory.

Rog
He sells identified rare equipment. When you purchase an item, he offers you to craft it for more Artifacts. He's looking for Order Artifacts and Scrap Metals are used for restocking.

Tujen
He wants to haggle with you and offers various currencies, gems, jewels and maps. If you try to lower the price too much, he can counter-offer or even remove the item from sale. His currency is Black Scythe Artifacts and Exotic Coinage is required in order to refresh his inventory.

During Expeditions you will find Artifacts (which cannot be traded) that are automatically picked up. There are 4 types of Artifacts (Lesser, Common, Greater and Grand) for each of the 4 factions to trade with the corresponding Kalguur NPC:

When you have an Expedition encounter, one of the four NPCs from the Kalguuran Expedition spawns in the area surrounded by various remnants and markers. When in the Expedition area, you can start laying 5 explosives to excavate it. The number of explosives can be scaled using Atlas Passives or Scarabs.

Upon detonating, the explosive chain will start and unearth monsters and chests within the range of every explosive. Explosives detonate in succession in the order you've laid them, giving you time to fight the monsters. Any marker within the explosives range unearths monsters or chests.

Remnants
You'll find numerous Remnants spread throughout Expedition areas. Remnants have a tooltip which add mods (One Prefix buffing the Monsters and one Suffix increasing the Rewards) to monsters and chests spawned from the explosion, but also all the subsequent explosions. This means the order you lay explosives is of the uttermost importance!

The idea is to first focus some Remnants you want to increase your rewards, and only then focus on Runic Monster markers while taking some Excavated Chests on the way. Take care of Remnants, as they can tremendously buff the Expedition monsters and can even grant them immunity to some damage types (those Prefixes being highlighted with a yellow text).

Look out for the Runic Monsters are Duplicated Prefix modifier, which is essentially a multiplier to your rewards. Then you want to focus the Suffix modifier increasing Expedition Logbook drops. Your next priority will be Stacked Decks, Currencies or Artifacts or anything else depending on your priority. Here is a list of all Prefixes and Suffixes Remnant modifiers:

Excavated Chests & Runic Monsters
Excavated Chests are marked with a sign with an icon on it. Chests can be common, uncommon or rare, uncommon having a yellow outline on the sign and rare an orange one. The rarer it is, the more Artifacts it gives you. They grant you various rewards depending on the icon that was displayed before the explosion and the Remnant modifiers. Those chests also reward you with Artifacts from the faction the Kalguur NPC in the event is interested in.

Runic Monsters are marked with skulls over spikes in the area and are different from normal monsters. They can drop Vendor Refresh Currencies, Artifacts, Expedition Logbooks and Ward item bases as well as all the rewards granted by the Remnant modifiers you placed in your chain of explosives.

Basics
During your Expeditions, you may discover Expedition Logbooks by killing Expedition monsters. They can be crafted like maps to increase Item Quantity, Item Rarity and Monster Pack Size. When you're ready, bring it to Dannig and open the Expedition Map to open your Expedition Logbook. These Expeditions are much larger than regular ones and way more rewarding. Expedition Logbooks offer up to 3 different locations with a different faction.

Implicits
Expedition Logbooks can randomly get 2 to 3 special implicits whose value can be rerolled using Blessed Orbs. The implicits related to Explosives, as well as the increased Number of Runic Monster Markers, are generally the best to focus on.

Layouts
Each location is a unique layout and comes with 2 special reward types. Each layout grants 10% chance for Excavated Chests and Runic Monsters to drop 2 special rewards. Some layouts also allow for better Remnants and Monsters positioning and a more efficient explosive chain.

Focus on layouts offering either great open layout for optimal Explosive Chain releasing, or great special rewards such as Scarabs or Simulacrum Splinters. The best layouts are highlighted in green in the following list while the worst ones are highlighted in red. The other layouts are decent.

Underground Areas
During your Expeditions, you can find Underground Areas containing some Runic Monsters and Reward Chests. To access them, you need to set up your Explosive Chain to free up the entrance. These Areas are affected by all the modifiers from your Explosive Chain. Their spawn is random, but you can rarely get a Area contains an Underground Area implicit on your Expedition Logbooks to guarantee one.

Bosses
Expedition Logbooks can sometimes spawn a boss you can identify through a skull icon on the minimap. To free the Boss and be able to fight it, you have to free him with an Explosive and they are affected by all the modifiers from the Explosive Chain like other rewards, meaning you want to set your Explosive Chain on the Boss towards the end of your chain. Expedition Bosses also drop more loot per Remnant affecting them. Each faction has its own specific boss:

These Bosses have special Ward Uniques, as well as Unique Iron Flasks. They also drop a bunch of Vendor Refresh Currencies (up to ~50) and a lot of Artifacts. While Bosses are randomly present in Expedition Logbooks, you can rarely get an implicit stating Area contains Boss.

Splitting Logbooks
Since Expedition Logbooks are highly randomized through layouts and implicits, it is a very common and profitable strategy to use Bestiary in order to split Logbooks. The best use for split are generally Logbooks with a guaranteed Boss Implicit Modifier and Dannig Logbooks with good Layouts and Implicit Modifiers.

Kirac
Kirac can sometimes sell you Maps with an implicit modifier:

You can find quite a few passives and notables related to Expeditions spread in 3 wheels in the Atlas Passive Tree: