Old One's Army Terraria: Official Event Guide
Quick Summary
- Defend the Eternia Crystal
- Tavernkeep sells essentials
- Three tiers of difficulty
- Build a spacious arena
- Sentries are crucial for defense
The Old One's Army is a unique tower defense-style event in Terraria, born from a collaboration with Dungeon Defenders 2. This challenging invasion tasks players with protecting a vital artifact, the Eternia Crystal, from relentless waves of Etherian foes. Understanding the event's mechanics is key to success, as enemies focus solely on destroying your crystal, not directly attacking you.
Your journey to repel this interdimensional threat begins with finding a special NPC, preparing a suitable battleground, and acquiring specific items. This guide provides all the factual information you need to successfully navigate the Old One's Army, from initial setup to advanced defensive strategies.
Preparing for the Etherian Invasion
- Tavernkeep NPC: You must first defeat either the Eye of Cthulhu or the Eater of Worlds/Brain of Cthulhu to make the Tavernkeep appear as an Unconscious Man in your world. Locate and rescue him, and he will move into an available house.
- Eternia Crystal and Eternia Crystal Stand: These items are purchased directly from the Tavernkeep. The crystal is consumable, meaning you'll need to buy a new one for each event attempt.
- Spacious, Flat Arena: A crucial requirement is a large, flat area for the event. The arena needs to be at least 123 tiles long (61 tiles on each side of the stand's center) and have at least 10 tiles of clear vertical space. Obstacles like trees or uneven terrain can prevent the event from starting. Enemies will spawn from portals up to 120 tiles away from the stand.
- Defender Medals: This unique currency is earned by defeating Old One's Army waves and is used to buy powerful sentry summons, armor, and weapons from the Tavernkeep.
Summoning the Old One's Army
- Rescue the Tavernkeep: After defeating a progression boss (Eye of Cthulhu or Eater of Worlds/Brain of Cthulhu), scour your world for the Unconscious Man to recruit the Tavernkeep.
- Purchase Essentials: Visit the Tavernkeep and buy an Eternia Crystal Stand and at least one Eternia Crystal. Consider also purchasing initial sentries like the Ballista Rod or Lightning Aura Rod to aid your defense.
- Construct Your Arena: Find or create a long, flat stretch of land that meets the minimum size requirements (123 tiles wide, 10 tiles high). Ensure no obstructions are present.
- Place the Stand: Position the Eternia Crystal Stand in the exact center of your prepared arena.
- Activate the Crystal: Interact with the Eternia Crystal Stand and place an Eternia Crystal onto it. This action immediately initiates the Old One's Army event.
Understanding the Event's Core Mechanics
- Three Tiers of Progression: The event scales in difficulty, unlocking new tiers as you defeat major bosses. Tier 1 is available after defeating the Eye of Cthulhu or Eater of Worlds/Brain of Cthulhu. Tier 2 unlocks after defeating any Mechanical Boss. Tier 3 becomes accessible after defeating Golem. Each tier introduces new enemies and greater challenges.
- Crystal Defense Objective: Unlike other events, your primary goal is to protect the Eternia Crystal from being destroyed by enemies, rather than just surviving yourself. The event ends if the crystal's health reaches zero.
- Waves of Enemies: The event unfolds in several waves, with increasing numbers and types of Etherian enemies, culminating in a boss battle at the final wave of each tier.
- Sentry-Based Combat: Sentries are a core mechanic, offering passive defense. You start with Etherian Mana to place them and gain more by defeating enemies. The Tavernkeep sells various powerful sentry types.
- Unique Rewards: Successfully completing waves earns Defender Medals, which can be exchanged at the Tavernkeep for exclusive weapons, armor sets (like the Tavernkeep's armors that boost sentries), and new sentry types.
Overcoming Challenges in the Etherian Defense
⚠️ Event won't start after placing the crystal.
Cause: The arena does not meet the size or flatness requirements, or there are obstructions.
Solution: Ensure your arena is a minimum of 123 tiles wide (61 tiles each side from the stand's center) and 10 tiles high with no blocks, trees, or other impediments in the direct path of enemy spawns. Verify the Eternia Crystal Stand is centered.
⚠️ Eternia Crystal is destroyed too quickly.
Cause: Insufficient defenses, low-tier gear for your progression, or incorrect sentry placement.
Solution: Prioritize placing multiple sentries, especially Ballistas for concentrated damage and Lightning Auras for crowd control near enemy portals. Upgrade your gear and sentries by farming earlier tiers for Defender Medals. Consider multi-player for easier runs.
⚠️ Struggling with specific enemy types (e.g., flying enemies, Ogre, Betsy).
Cause: Lack of appropriate weapon types or poor positioning.
Solution: Utilize weapons with piercing or area-of-effect for large groups. For flying enemies like the Etherian Wyvern, use vertical defense or ranged attacks. Against tough bosses like the Ogre or Betsy, focus on high single-target damage and mobility. Consider specific buffs.
⚠️ Not enough Etherian Mana to place sentries.
Cause: Not collecting mana dropped by defeated enemies.
Solution: Keep an eye on the battlefield and collect Etherian Mana dropped by fallen foes during waves. This is your primary source for deploying more sentries.
Building an Impenetrable Crystal Defense
- 🔒 Strategic Arena Design: Build an optimal arena. A completely flat ground with an asphalt layer can enhance player mobility. Consider elevated platforms for better sentry placement or to deal with flying threats. Actuating blocks around the crystal can create a drop arena, making ground enemies less effective.
- 🔒 Sentry Placement Mastery: Place Ballistas near the crystal for direct damage on bosses and tougher enemies. Position Lightning Auras closer to enemy portals to neutralize weaker, faster foes before they reach the crystal. Experiment with Exploding Traps for additional crowd control.
- 🔒 Buff Potions and Food: Consistently use buff potions (e.g., Ironskin, Regeneration, Lifeforce, Endurance, Wrath/Rage) and ensure you have the Well Fed buff for enhanced stats. Time their use to maximize effect during critical waves.
- 🔒 Focus Fire on Key Threats: While sentries handle the bulk, prioritize your own damage output on high-threat enemies like the Dark Mage, Ogre, or Betsy, which can quickly devastate your crystal or overwhelm your defenses.
- 🔒 Utilize Multiplayer: The Old One's Army event becomes significantly easier with multiple players, even with health scaling. Coordinate roles, such as one player defending one side and another handling the other, or focusing on bosses.
🎧 Official Support & Help Center
For general Terraria game support, please refer to the official Terraria community forums or the comprehensive Terraria Wiki. There is no specific direct support channel for this in-game event.
Answering Your Etherian Army Questions
Q: How do you start the Old One's Army event in Terraria?
You start the event by placing an Eternia Crystal onto an Eternia Crystal Stand in a sufficiently large and flat arena. You must first acquire both items from the Tavernkeep NPC.
Q: What is the Eternia Crystal in Terraria?
The Eternia Crystal is a magical artifact central to the Old One's Army event. Your primary objective during the event is to protect this crystal from being destroyed by incoming waves of enemies.
Q: How many tiers does Old One's Army have?
The Old One's Army event has three distinct tiers. Each tier increases in difficulty and unlocks after defeating specific game progression bosses.
Q: Can you do Old One's Army in pre-Hardmode?
Yes, Tier 1 of the Old One's Army event can be done in pre-Hardmode after defeating the Eater of Worlds or Brain of Cthulhu. However, higher tiers require defeating Hardmode bosses.
Q: What rewards do you get from the Old One's Army event?
Successfully completing waves in the Old One's Army grants Defender Medals, which are a unique currency used to purchase special sentries, armor sets (like the Tavernkeep's armors), and powerful weapons from the Tavernkeep.
Wrap Up
The Old One's Army event stands as a unique and rewarding challenge within Terraria, blending traditional gameplay with tower defense mechanics. By understanding its requirements, mastering its unique combat system centered around sentries and crystal defense, and preparing effectively, players can overcome the Etherian invasion and reap valuable rewards. Embrace the strategy, protect your Eternia Crystal, and emerge victorious against the Old One's Army.