The Eradicator is - next to the Constrictor, the Purifier and the Enslaver - one of the four Guardians of the Elder. In order to fight him, you have to open an Eradicator occupied Map. These Elder Influenced Maps have a special Boss Icon in place of the typical Map Icon. Defeating an Elder Guardian for the first time unlocks a favourite Map slot for your Atlas.

Each of the Elder Guardians drop a specific Map Fragment that is required to face the Elder. The Elder and the Shaper drop different map fragments that are needed to open portals to the Uber Elder Encounter. Defeating the Uber Elder for the first time rewards you a Decayed Voidstone that can be socketed into the Atlas.

Elder Guardians - Boss Guides:

The Elder - Boss Guide:

Elder Guardian Maps can be dropped upon killing any regular T14+ Map Boss on the Atlas and have 2 implicit modifiers:

Area is influenced by the Elder
This implicit modifier adds the Elder influence to the Map, adding Elder monster packs

Map is occupied by The Eradicator
This implicit modifier adds the Eradicator as the new map boss, replacing the default boss of the area.

You can increase the drop rate of these Maps with the Atlas Passive skill Remnants of the Past. You can also obtain Elder Guardian Maps from Kirac or encounter an Elder Guardian as part of his Atlas missions. These Maps can also be acquired by getting Map rewards in other League Mechanics such as Tujen from Expedition, Delirium or the Ritual Altar.

An Elder Guardian Map can be converted into another Map via an Orb of Horizon and even upgraded in Tier with a Harbinger's Orb. However, you cannot change the Guardian that is occupying the Map itself.

Defeating an Elder Guardian counts as clearing the Map in terms of Master Missions and unlocking them for your Atlas. Note that Maps that are occupied by an Elder Guardian do not grant the Map completion bonus, since the Elder Guardian replaces the default Map boss.

It is possible to have multiple influences on a single Map. As an example, while in an Elder influenced Map, you can also encounter any of the Conqueror's of the Atlas invading it. This makes your Map more rewarding, but also increases the difficulty.

In addition to regular loot, the Eradicator has the following boss-specific drops:

Once you encounter the default Map boss in an occupied Map, the Elder appears to dispose of it and open a portal to the Guardian's domain. Make your way through the portal and find the Guardian locked in a Cocoon. The Elder starts summoning the Guardian, which is vulnerable as soon as the ritual finishes.

Make sure to check out the Skills Breakdown above to learn more about each of the abilities.

The Eradicator can spawn in one of three different zones:

At 66% and 33% health respectively, the Elder appears to teleport both you and his Guardian into another phase with new hazards to be dealt with.

Phase 1 - Lightning Pillars connect with a beam to the center of the arena, dealing damage when touched.
Phase 2 - The area is surrounded by Lightning Pillars, activated in a circular pattern.
Phase 3 - Lightning Spires are placed into the arena, shooting Lightning Beams around them once active.

Phase 1 - The arena is split into 5 different areas, while the outer zones periodically fill with lightning.
Phase 2 - An Energy Vortex is placed in the middle of the area, shooting Lightning Orbs in random directions.
Phase 3 - Lightning Mines are placed in straight lines, detonating after a short period of time.

Phase 1 - Lightning Spires periodically connect with a Lightning Beam, dealing damage when touched.
Phase 2 - Large Lightning Orbs are sent across the arena following a straight path.
Phase 3 - Lightning Pillars activate occasionally, floating the area with small Lightning Orbs.

The newly revamped Atlas Passive Tree provides us with additional ways to empower Bosses and enhance the Pack Size and drop chances of Shaper and Elder influenced Maps:

Good Luck, Exile!

Written by mbXtreme
Reviewed by wudijo