Eternia Crystal (NPC)

**PC/Console/Mobile/tModLoader/tModLoader 1.3-Legacy-Only Content**: This information applies *only* to the **PC**, **Console**, **Mobile**, **tModLoader**, and **tModLoader Legacy** versions of *Terraria*.Eternia Crystal***Map Icon***Statistics

Sounds

* Internal NPC ID: **548**

This article is about the NPC. For item used to start the event, see Eternia Crystal.
The **Eternia Crystal NPC** is a background object that is the centerpiece of the Old One's Army event.

Right-clicking the Eternia Crystal Stand with an Eternia Crystal in the player's inventory will place the Eternia Crystal on the stand. After a 5-second countdown, the Eternia Crystal (now considered an NPC) must be protected from waves of enemies from the Old One's Army who will prioritize attacking it. If the Crystal is destroyed, the event ends in failure. If it is kept "alive" until all waves are cleared, the event is won.

Both the Eternia Crystal and its stand are purchased from the Tavernkeep for 25 and 1 respectively. A long, flat area is required in order to place the Eternia Crystal successfully and summon the event; otherwise, the Eternia Crystal will reject the area and pop out of the stand, able to be picked up as an item once again.

## Notes

* "You'll want to place your Eternia Crystal stand in a pretty open, flat area. Lots of walls and stuff might make it pretty difficult to protect!" – Tavernkeep.
* A minimum of 61 blocks of flat space is required on either side of the Eternia Crystal Stand, measured from the column clicked.
* If adequate space hasn't been provided to either side of the Eternia Crystal Stand, the game will announce the following status message: **The eternia crystal rejects this area and pops away instantly, the Tavernkeep mentioned it should rest in a large flat open area...**
* Once the Eternia Crystal is placed, players are inflicted with the Creative Shock debuff for the duration of the Old One's Army event, which prevents the removal or placement of blocks during the entire event. All players within 180 horizontal blocks and approximately 55 vertical blocks of the center of the Eternia Crystal Stand will be affected by this debuff. The Ice Rod can still be used, but it will not block enemies since they can phase through blocks.
* The Eternia Crystal's life and defense are dependent on the player's tier: pre-any Mechanical Boss, post-any Mechanical Boss, and post-Golem. It should be noted that although the life and defense increase with each tier, so does enemy attack damage, as the enemies become increasingly more difficult with each tier.
* The Old One's Army event will commence with the status message: **The old one's army is approaching!**
* The Old One's Army event will end (if the player is victorious) with the status message: **The old one's army has been defeated!**
* Though the crystal itself is immune to explosive damage, the Stand and the blocks beneath it can be broken due to the explosion. This will cause the crystal's sprite to fall until it reaches a solid block once again.
* The Crystal NPC can be moved by Hoiks. If utilized correctly, this can make the fight much easier.
* The Eternia Crystal NPC can be damaged by Rotten Eggs, so care should be used if they are utilized around the Crystal NPC as a weapon.

## Trivia

* The crystal's map icon is the same as its inventory sprite.
* The crystal's sprite will have cracks in it as its health decreases.

## History

PC version
* Desktop 1.3.4.3:
	+ T3 health reduced from 10000 to 5000.
	+ T3 defense reduced from 45 to 20.

* Desktop 1.3.4: Introduced.

Console version
* Console 1.17: Introduced with changes from Desktop 1.3.4.3.

Mobile version
* Mobile 1.4.0.5.0: Introduced with changes from Desktop 1.3.4.3.

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